need to rant about fiancé's work

So my fiancé is supposedly meant to be paid £200 every Friday plus the commission he makes. Every Friday we seem to be getting less that what he suppose to. He's getting a promotion in the 1st October where he's meant to be getting £300 a week but I just don't see this happening. We're moving into our own place on the 3rd of October and are going to need consist money coming in as the council will just chuck us out of the flat. I feel awful for my fiancé as he works his arse off and seems to get nothing for it and he's also getting annoyed at me for keep going on about it to him but it's like I can phone his work and moan to them. I feel like we're banging our heads against a wall.