Please take this as constructive.
You removed the cylinders.
Sounds as if they froze after firing some rounds. A blackpowder revolver requires more clearance between the cylinder face and the barrel. May not be the reason they froze, but some remove a touch of metal off the barrel face. The barrel gap is not crucial when firing blackpowder blanks. However; if you do this, you will create a problem shooting live ammo.
When you cock the revolver, a "hand" moves up and out of the recoil shield catching the star on the back of the cylinder and rotates the cylinder. Remove the cylinder and look at the slot at about 3:00 on the face of the recoil shield. When you cock the revolver, does the hand appear and push upward?
The "bolt"/cylinder stop may be part of the problem. Pick up the revolver as if to shoot. (All warnings of a loaded weapon apply!!) Turn the gun upside down and point it to the left if your strong hand is the right hand. At the bottom of the cylinder you will see the bolt stop protruding from the frame and resting inside a cylinder notch. Keep the revolver upside down pointing in left, begin to cock the revolver. The bolt should start to disappear into the frame. When the next cylinder notch approaches the vicinity of the bolt stop, the bolt will pop up just prior to the notch finally seating and locking the cylinder. Timing and/or a spring could be the culprit if it does not function as stated.
Brand new, I am sure they will fix or replace. Borrow it if you have to, but get a pair of NM Rugers.