Renault Megane key won't lock or unlock doors!?

Hi,
I have a 2004 Megane and about 2 months ago the key wouldn't lock or unlock the doors. I spoke to my mechanic and he said these keys are prone to problems and to gently apply pressure to the key pad in different locations as the circuitboard could be loose. This seemed to work and I managed to unlock the door but then couldn't lock it again so it has now been unlocked for 2 months! Also, we used to have remote entry so if in proximity of the car the doors would unlock and we also did not need to insert the key into the key holder to start the car. Since the problem with the doors if we don't insert the key it says card not detected and won't start. I am lucky I can start the engine but not happy about leaving the doors unlocked!!! Any suggestions? We live near Cambridge.

Thanks