My ford puma won't lock?

Hi,
My central locking remote has not worked for a long time - tried a new battery (twice), reset it - worked for one or two times then nothing. so gave up on that and have just used the key in the door. Now my doors won't lock. It just flicks back open - well whirrs more like it. I've no chance of taking it to be fixed until I get paid at the end of the month :( I'm having to risk it and leave it unlocked. Has anyone one any ideas please? 2001 Puma.

Thanks