Can you explain what you mean when you say the keypad sticks? Are you suggesting something along the lines of a sugary drink has been spilled over the keypad causing the actual buttons to be contaminated in some way? If so, this would be a case of isloating the power and stripping down the keypad, popping out the rubber button mat and giving it a good clean with Electrical Contact Cleaner spray.
Rupert
March 2020
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home alarm systems.