I surrendered my cat and regret it am I able to get him back ?

You should call to find out their policy.

Yes, but you'll have to adopt him back. So pay the fee because they've probably already neutered him and/or given him shots.

You'll have to call them to ask that question.

You'd have to pay a fee to adopt the animal just as if you were a new adopter, and actually, if you've surrendered an animal, they usually will not okay an application to adopt. That was what I experienced while volunteering.