It's most likely a relay issue, deletion requests I've tested are all working and I haven't made changes to the deletion code recently. What relays are you connected to in settings?
Does this look right? I don’t think I’ve ever changed them in Shopstr but maybe another client did. https://nostrcheck.me/media/cbb249582ac48938a02ff7ce2f57ed47c548b93af11a00fe29be008b6581f9b2/d0e65be3e391cf51592771090a56d9d9b17c02d67c5904f0c8adc2fa86d31a98.webp
Yeah, those are the defaults. With the sendit relay it should be publishing the deletion requests properly, so it might actually be a caching issue. I'll look into it a bit more this weekend.