I’m afraid to try my hand at interpreting this excerpt from a 2014 China Times article:
今年沒有所得憑單，又要如何查詢所得資料呢？官員表示，納稅義務人可從四大管道查詢所得資料，而憑單填發單位仍有義務填發憑單，民眾不必太擔心。
查詢所得資料的四大管道包括：一、以自然人憑證或財政部核准的金融憑證，透過網路查詢所得；二、每年5月報稅季時，可親自或委託他人至國稅局臨櫃查詢。
第三、屬於稅額試算對象的納稅人，可參考國稅局寄發的稅額試算通知書，上面已羅列各項所得資料，相當方便；第四、若上述方式都不合用，財政部建議，納稅人可向憑單填發單位申請填發憑單。
Is there anything in there that might help?
this might be related. I have not read it yet, though.
1406 扣扣繳義務人已依規定扣繳稅款未依規定填報或填發扣繳憑單，會受到什麼處罰？
今年沒有所得憑單，又要如何查詢所得資料呢？官員表示，納稅義務人可從四大管道查詢所得資料，而憑單填發單位仍有義務填發憑單，民眾不必太擔心。
An official says there are four ways to check income information, so the public should not worry.
查詢所得資料的四大管道包括：一、以自然人憑證或財政部核准的金融憑證，透過網路查詢所得；二、每年5月報稅季時，可親自或委託他人至國稅局臨櫃查詢。
第三、屬於稅額試算對象的納稅人，可參考國稅局寄發的稅額試算通知書，上面已羅列各項所得資料，相當方便；第四、若上述方式都不合用，財政部建議，納稅人可向憑單填發單位申請填發憑單。
1406 扣扣繳義務人已依規定扣繳稅款未依規定填報或填發扣繳憑單，會受到什麼處罰？
Penalties for (the employer) failing to report withholding of income or issue a statement.
Of course you asked for a weekly or whatever receipt payday.
If you haven’t you must get into the Tardis and go back.
Traditionally, local firms will try to falsify your W2 Forms and under report your income. Cool schools will split the difference. A certain 4 letter chain actually had two sets of books back 20 Years ago.
Local people will try to state you make so little that your owed no taxes. It happened to me. The boss would try to keep it all.
Now, it is important that anyone working in Taiwan get a written statement of their gross pay and take home pay listing each deduction.
With that proof, you can just threaten to go over to the Tax Office in your county and report him. Came close many times.
Thank you all for your help. However, I’m still a little unsure as to how to proceed from here. The school has finally responded after I threatened legal action and they said we have to go to the school and pick them up in person. Of course there is no way we can do this as we have no plans to return to Taiwan. And the only people we knew in taiwan were connected to the school.
Hi! Thanks so much for your offer! Unfortunately the school is in Zhubei, it’s a 5 minute walk from the Hsinchu HSR station which is a 30 minute ride from Taipei. But if you did fancy the trip I’d definitely be prepared to compensate you for your troubles, especially if it meant we could get the statements!!
They’re not willing to scan and email them to you? (Not as reliable as having the originals, but better than nothing.)
The tax office said there is no problem with sending them an emailed copy, the school is just being deliberately awkward.
Did you quote the administrative penalties in your legal threat? Was it written in Chinese? That might inspire them to take the matter more seriously.
Unfortunately I don’t have anyone who I can ask to do so in Chinese. Perhaps copy and pasting the sections you kindly found for me would be a start but I’d rather send a full legal threat in Chinese. Can you or anyone out there recommend a lawyer who would send a threatening letter to them? I’d be willing to pay for some legal correspondence if that’s what it takes.
What a lawyer would charge might be more than the amount of money that’s at stake here.
I’m a little busy with Christmas cheer right now, but PM me if you can’t find anyone to be your proxy. 
Of course, merry Christmas!!
Please let us know the outcome. You really have a slamdunk easy case. You just need to show up with your threat of punished, preferably in the form of a printed bilingual copy of the regulations.
You also need to be accompanied by a local or veteran foreigner who went through this before.
You will get what you need and maybe an appolgy for the misunderstanding. Not wrong doing, just a misunderstanding mostly due to your poor communication skills.
On an other subject, you need to make local friends and build local contacts. My girlfriend’s family and the local proprietors of the local electronic fixit shops acted as my lawyers, if you will…
I became friends with the computer fixit guys because our mutual interests.
Thank you for your input, but as you will see from my previous posts I no longer reside in Taiwan, therefore am unable to “make local friends and build local contacts”. I’ve lived all over the world and have never had issues like this but perhaps it’s due to my “poor communication skills” that you’ve picked up upon through my communication within this forum?
I’m really just looking for some current advice rather than being lectured on how to retrospectively fix the issue at hand here.
I’m sorry. Ouch… I said Sorry in Taiwan. I did not read carefully. You remind me of how I was. Taiwan is unique. By poor communication skills, I meant … well. You can speak perfect Chinese but you will always have poor communication skills. They will blame you for the misunderstanding.
You’re lucky, you escaped. Just a question. Why do you care about getting your Taiwan Taxes in order? Are you trying to get a refund? You are free. Unlike you, I needed all of my ducks in a row to get the visa and marriage approved.
You just need one of the old time forumosans who live near you go and argue on your behalf. Every one who owns a business or a school is skirting one or more regulations. Because you are not there they don’t see you as a threat.
As soon as you have an easy and presentable case, they will discover that it was all a misunderstanding. Taiwanese don’t want to be looked into . You will have your settlement. again, sorry for putting you down. You are reasonable, this place is unique.
That doesn’t sound like too bad a trip…what sort of document would be needed to “prove” I was acting on your behalf? (Anybody? Anybody?) And can we get a link to the provisions so they can be printed out?
I’m not sure; is the needed document on the page linked below?
The first link on the page, the link that says, “空白書表-中英對照(odt),” seems to link to a document in Indonesian and Chinese.
The second and third links on the page, the links that say, “空白書表-中英對照(word),” and “空白書表-中英對照(pdf),” seem to link to documents that have a Chinese version and an English version.
In my case, clicking any of those links caused a download dialogue to pop up, rather than loading the document directly into the browser. Perhaps that’s what anyone else would encounter.
Hope this helps, or at least doesn’t add any significant confusion or frustration.
If they really want to be 
about it they might ask for a 委託書 from the TECO/TECRO, but they’ll probably give up once they perceive the threat as genuine, do the math for the admin. penalty, and don’t have any real doubt that you’re the authorized representative.
I’ll see if I can find the regulation.