Can a member return pension funds and have their T4A amended?

I work for a Pension Administration Company that administer registered pension plans.

We have a 71+ member who had a ITA minimum payment scheduled for December '21.
Throughout the year she took out a couple lump-sum payments. On the LSP request forms, we have a line that says “I understand this Lump Sum Payment request does not replace my Scheduled Payment Instruction” (so we did communicate that LSP’s do not effect scheduled minimum payments).

She assumed because she took out lump-sums, her scheduled payment in December would be the minimum amount less the lump-sums she took, but it wasn’t, it was for the full ITA minimum amount.
She received the funds, she received her T4A slip, and it was filed with CRA.

Now she is essentially “changing her mind” (because she took out way too much money and has high taxes), and wants to return the funds and have her T4A amended. We told her that there is nothing we can do to put the money back, but that she could put the money in a TFSA or talk to one of our retirement consultants for other options. She is being difficult and saying she is a professional accountant and knows this can be adjusted with CRA.

Does she have a leg to stand on? Can she just give back 2021 money and have her T4A amended?