Redeeding Gift codes

Hello SS community

I have used SS for 3 years at my shop which has both products and services.  We do a lot of gift cards and need some help.

People have no problem using their gift card online booking an appointment. However when people come in to shop for products, there are issues. Previously, you could edit the remaining balance on a gift card to reflect the amount left after they've shopped, but SS removed this capability.  It makes it VERY hard for us to track unless they use the entire amount of the gift card. Theoretically since we cannot deduct any amounts from the balance of the gift card, people can use the gift codes again and again.  please Square space & people - help us figure out what to do, lest we switch to another system that is more user / business friendly.