How old is the uvb light? It should be replaced after 6 months. Also, is it a tube light or a bulb for your uvb? It should be a tube.
That black crate is in the cage? Try to use plants when getting the cham to drink, it looks dehydrated. You may want to get a rubber syringe and give it water that way to ensure it goes down.
The crickets you are feeding it are eating what? They are only as good to your cham as much as you keep them healthy. Read up on proper gut loading, it is very simple and helpful in the long run.
Also try silk worms, easy and nutritional!
do u know humidity? also a big problem with chams.
And if you just got the cham this way, then there was nothing you could have done up until this point. It may just take time for the cham to settle in and become comfortable and start eating.
Good luck!