Here is my personal story. I am happy that the outcome was favorable.

The final year I attended school, I made a tuition payment eligible for the American Opportunity Tax Credit (which was $2,500 tax reduction, a credit is much more powerful than a deduction). There is a maximum of 4 credits per taxpayer (previously 2 under the Hope credit rules prior to expansion to 4 years). You can take the hope credit for the first four academic years of tuition. Practically, this spans 5 tax years or more sometimes as academic years are based on credit hours (most taxpayers and even accountants don't know this but I've read the hope credit regulation front to back). My parents took the credit 3 times while I was a dependent, and skipped the 4th year, and I claimed the credit on my final year when I wasn't a dependent due to having a full time job to support myself.

I received a IRS notice indicating I owed $3,000 because I did not receive a 1098-T from the educational institution demonstrating that I paid eligible tuition expenses. They billed it in the fall of the previous year and reported it on the previous year Form 1098-T.

The irony here, is that educational institutions are permitted to issue Form 1098-T on an accrual basis when tuition is billed. However, the taxpayer entitlement to a credit is based on a cash basis. I can't think of a dumber rule to be honest (see sidebar at the bottom).

Long story short, the final year I made a tuition payment to claim my fourth AOTC credit (there is a maximum of four total), I received an IRS notice for $3,000 due.

It took 10 months to clear up the notice. Being a tax accountant I drafted a long powerful response with support of my payment in the final year in which I had not received a 1098-T. I wrote an explanation of why Form 1098-T was elected as accrual basis by the university and I would not be able to produce a 1098-T on a cash basis for this reason. I cited not only Form 1098-T explanations but the regulations for the hope credit (later AOTC credit) and the regulations for the 1098-T requirements.

The IRS rejected my initial letter and re-affirmed I owed.

So I had to have my uncle that is a CPA get involved (and I didn't have this designation at the time only recently graduating). My uncle put my explanation on his letterhead and sent it in. Result: 4 months later they dropped the bill.

Side Bar
The IRS is in the process of changing Form 1098-T to avoid issues like this in the future by requiring universities to report tuition on a cash basis (when paid): https://tax.thomsonreuters.com/blog/onesource/what-a-new-irs-change-to-form-1098-t-means-for-colleges-and-students/