Truworths don't deserve support

I have a credit note for Truworths which was issued on the 14 of May 2022 only to know today that I can no longer use it after 3months. I did contact truworths service and notified them its just over a month but was refused. I do not think it's fair something that a customer paid for was put on a credit note but can no longer use it now so my money is gone to truworths for nothing. What do truworths do with the credit note? Not considerate enough to understand that this is people's money on the credit note and should be given a chance to use it not just take it