Had to sell sons Xbox because of his behaviour

hi guys well my son has been badly behaved for quite a while and I had told him that if he continues he will not have his Xbox back as the consequence which I think is totally fair what about you ?

I actually think it’s fair as long as it was clearly explained beforehand and followed through consistently. Kids are pretty good at testing boundaries, so if the consequence keeps changing it can make things worse.
That said, selling it is quite a big step - did he understand it was a permanent consequence? Sometimes we found time-limited consequences worked better so they have a chance to earn things back and learn from it.
Either way, sticking to what you said matters more than the specific punishment in my experience.