Dear Felix
This is to acknowledge receipt of your letter of [date], in which you requested an extension on your [type of] loan, number [#].
After careful review, we regret to inform you that we are unable to grant you any further extensions for the payment on your loan.
We are sorry about the difficulties you are experiencing, but we must insist on receiving your payment by [date]. We hope that you will be able to find another solution to your problem.
By:Lydia