Mounting screws won't thread / tighten

Hi @Marley_Ring can you help please. I have had my x2 doorbells for sum time now and never had a problem. I removed the door bells to charge and noticed that the black plastic around where the screws go to fit to the wall has started to crack and now the screws will not tighten up to secure? I do have a plan in place. What can I do or what can be done to fix this?