"They also said that I could claim the full amount I paid for tuition and qualified expenses in 2020 since I paid for them in 2020 and wasn’t reimbursed in 2020".
Yes, but not exactly. Usually, you may not claim a tuition credit for expenses paid (or reimbursed ) by tax free money (e.g. scholarships, grants, VA benefits or employer reimbursement).
But since the reimbursement was received in a different year, you have a choice (actually a tax loop hole). You can claim nothing on your 2020 tax return, since it will be reimbursed in 2021. Or, you can claim a tuition credit, based on that money, because you are out-of-pocket. But then, you have to report the reimbursement from your employer as taxable income on your 2021 tax return.
It should increase your 2020 refund by $1100 (assuming you have that much tax liability), but should only result in $132 additional tax next year (assuming 12% tax bracket). See previous comment about deferring the AOTC.
