RECEIVED SMS LATE !!!

Good day. I normally receive an sms asking whether I would like to just pay capital and fees at the end of the month. I received the sms this month, but after the offer expired (i.e. received it on Sunday and it expired on Saturday). Your call centre agents say that nothing can be done in this regard. I have a copy of the sms that I can send to prove that it was received late. How can I respond to something after it had already expired.