Replacement seat strap for Crescent Ultralite

My aunt & uncle both have Crescent Ultralites that they bought from Headwaters a few years ago. The straps on the back of the seat (that attach to the kayak) have worn out and broke—probably due to sun exposure. I’d like to buy replacements but I can’t find them anywhere. Does anybody know where I can find them?

Pics? Maybe retrofit something w this.

https://topkayaker.com/index.php?main_page=product_info&products_id=1113