Boiler trouble and cowboy gas servicer?

we moved into a new house a few months ago, during that time it was very warm outside so i had no reason to turn on the heat, but now its getting chilli and when i try to turn it on it wont work! it make noise as if its on but no flame, i got a guy from gas board to come and he supposedly fixed it by changing some part and it worked for a little while yesterday but not any more, what cud be wrong wid it? oh yeah and the guy said he wasnt sure wats wrong and he was gonna leave then he came back and changed the part anyway (i found a fuse dropped down the toilet after he left) so he charged me 360 euro for a fuse that cost 50 cents!. and still no heat, wat shud i do?