re tailgate lock and immobiliser?

last week pushed plastic tailgate lock in on my renault megane scenic 1600. it wedged open but the tailgate itself will not open.
since then and the change in weather (been told it could be a factor) when turning ignition key engine turns but wont fire - told linked to immobiliser.
instructed to open all doors, close them, lock with key fob, walk away, sneak up on car unlock and bob's yr uncle. this has worked twice but this morning no joy. what can i do?