my leopard gecko..

Question
I bought a leopard gecko that is about six months old three weeks ago and he hasnt eaten anything since i got him. The temperatures are all correct and he has a humid hide away. I use reptile carpet instead of sand so he doesnt get impacted but im wondering if he could have an impaction from the sand they used at the store. My other leopard gecko eats well and i try to separate them when i feed them so they each get the same amount of crickets but he shows no interest in them at all and the other gecko ends up eating them in the end.

Answer
I would say you need to return it immediately.  3 weeks is far too long for it to go without eating. Something is wrong and it should be exchanged.  If that is not possible I guess the only things left would be trying different food (worms perhaps) or a vet visit.