toilet soil pipe leaks?

My soil pipe that comes out of the wall is slightly angled so ANY push on fitting to the toilet leaks slightly as water accumulates in the fitting (Prob due to gravity!) .
I have had 2 toilets fitted but they and every one I have looed at in shops all have a soil outlet that is slightly lower than the wall one. Plus theres the agle problem. I have tried the flexible concertina type but didn't work either. Help! I can't afford a builder to re-do the original soil pipe.