Updating wix stores inventory on add to cart instead of after purchase with wix code?

Hey guys! I have a major problem and I could really, really use some help from a moderator or anyone with info on this issue. My client is flipping out (as am I) because a customer was able to purchase more of a product than what was in stock today. They had 3 of a variant of a cup in stock, the customer added 4 to cart and was able to complete the transaction, and the inventory was updated to -1!!! This is a major issue for them as their stock is limited, when it’s gone, it’s gone. Now they are having to reach out to the customer, offer a discount and substitution, apologize, etc. I could really use a fix for this while waiting on a solution from support. Is there a way to fix this issue with code?