Are the buttons harder to press than normal?
does this happen if your stood 1 mile away or 1mm away from the car?
Maybe its just given up :unsure:
Mine did stop unlocking, i took it aoart and the unlock microswitch had come away from the circuit board, i put it all back together and its worked since.
Might be worth taking apart and looking for anything obvious...
could be micro switch burningout in remote you can buy theses on ebay for a quid and if ur a compitant at soldering the new part on then your laughing