Our scooter had thsi issue. It was a severe case of impaction. He did not poop for what we noticed about a week and half or 2 weeks straight. He ended uplosing all mobility in his back legs and tail. We eneded up getting him to poop by feeding him once a day 1cc of mineral oil at night and that did the trick to break up the poop and let him go. Within 2 days he was almost 100% better and now he is just fine.
We went to the vet when we noticed he was inpacted and also when he finally pooped. HE ended up having a parasite called coccidia. It is a pretty normal parasite that chams and dogs and cats get that a normal parasite vaccine will not get rid of. You have to get a special kind to kil it off. What the coccidia does (from what i understand) is it causes his digestive tract to quit working and this causes impactions and eventually death.
Bring a sample of his most recent poop with you and go to the vet. Without the poop the vet cant know for sure if he has any kind of parsite. IN our case, he would still be sick without it, maybe dead.
thankfully though he is regaining his weight and littering his poop all over our cage. we r sooooo happy!
-Justin