Answer:
You have a breach of contract. Any reimbursement should be coordinated with your legal counsel to insure you alleviate as much civil liability as possible.
This will most likely be a big undertaking, depending how far back you have to go. You will have to back off any payments to date, input the correct rate(s) and reapply the payments to get the proper charges and then refund the difference between them and the improper charges.
First published on BankersOnline.com 12/5/11