If the keypad doesn’t work, that’s a device failure, and you would need to talk to the manufacturer. There isn’t anything you can do from the smartthings side, unfortunately.
If you happened to pay for it with a visa card in the US you may have an extended warranty benefit which adds an extra year to the manufacturer’s warranty, so that can help.
Other cards may have similar benefits, so look into that if you used a credit card for the purchase and the warranty has expired.
But first talk to the manufacturer for troubleshooting.