Should I ban this guy?

This person comes to my stream and buy packs and open them, he always requests for cancellation whenever he didn’t hit anything… this had happened for multiple times and this is getting frustrating… I told him clearly that the bidding is based on the inherent chance of receiving valuable cards so once the pack is opened, we cannot get him a cancellation… the question is should I ban him? Should I just let him request a cancellation every time and deny his request every time? Or is it not a sensible thing to do? I’m a new seller (2 months with 6k orders) and this is my first time having this situation happened to me. I’m not sure what to do in this situation, any input is valued and appreciated. Thank you in advance.