A buyer bought 4 cameras in a single transaction

A buyer bought 4 cameras in a single transaction. However I just found I only have 3 in stock now.
It is my fault not monitoring inventory carefully. What is the best way to solve this problem now?

can't help you but I will tell you something you may not have known ------ example ----- you have a listing and you have 10 items (in one listing) on the BIN and you sold 5 - when that item gets re-listed the quantity will be 10 still and you have to change the quantity to the number you have on hand

didn't know if you knew that but I found it out by mistake long time ago and it is a cheesy little mistake that can cause you problems


You'd better let the buyer know you only have three, with profuse apologies for your error.

I think you should base what you do after that on the buyer's reaction. Some buyers are understanding and might be happy with three. Others might specifically need four. Still others will be angry.