upvc door handles?

My door is about 12 years old and I can't remember the company that fitted them - doubt they are around anyway.
I locked my front door yesterday and then tried to go out in the afternoon. The door appeared to unlock but I can't get the handle down from either inside or out. Do I need a new lock, handle or what. Any ideas as I can't afford a new door. Problem is how do I get it open to change the lock if that's what's needed. Please help