Electronic Key Pads are not the problem. The problem lies with misuse of the safe. If you side load the locking mechanism, locking parts, gears, and motors can be damaged.
If you take the face of the Key Pad off, you will see a small hole near the top.
Put a small screw driver in there, applying pressure against the mechanism while entering the combination. You might get lucky and it will open. If that doesn't do it for you, invest the money and get a safe repair company out to fix it for you.
Had a similar problem last year although I did not slam my safe door. What I was doing was holding the door closed against pressure that was trying to keep it from closing…one of the door mounted guns was contacting a shelf thus "side loading" the locking mechanism. The way to prevent this in the future is to gently close the safe door and before engaging the lock, make sure the door stays completely closed on its own (assuming the safe is level). If it tends to creep open, check and make sure nothing is preventing the door from staying shut and if there is, change its position which will correct the situation against future problems.