American WEB Loan Refund

I have managed to get a paid in full from American WEB Loan but trying to get a refund from them is close to impossible.  Not sure how I should proceed with their latest response.  I have overpaid them by $1200 and they are illegal in the State of Michigan.

Dear Valued Customer,

I see in the chain that you did receive my email advising that we have forgiven your active remaining balance, we are not going to be able to offer you the refund you are requesting. As a returning customer, you entered into your loan fully aware of the payment options, you chose by default to simply pay fees and extend your loan out. Please refer to your loan agreement to answer questions regarding our billing process.