wat can i do?

[frilly]

My son had a dignosis of Aspergers/ ASD and has a Statement of Special Educational Needs. He is now 12 and been at his mainstream secondary school with support since Sept.
Now throught most of his primary years he was excluded from trips/days out due to his behaviour but he didnt get much support there and thought things would be better at secondary because it has its own specialist unit.
He was promised a residential trip from the start which was in April... he ended up excluded from that.
Now for a couple of months we were looking forward to him going to ********** Valley with the rest of the year... with support.
That trip was today, (Mon,) and didnt know if he had to wear school uniform so i phoned them first thing. Someone called back and said he wasnt allowed to go and that they had tried to phone me on Fri to let me know..(didnt try hard as they hadnt left a message and they didt try my mobile!)
There have also been a 'reward' scheme where he get rewarded for being good. Only his teachers are sometimes too busy to sign it so that doesnt count even thought he has been good.
Now i am fed up with people messing him around, telling him one thing and then at the last min sayin otherwise, im not surprised he gets moody at school if they are bribing him with things then taking it away at the last min.
I have tried to explain but then feel so intimadated when the staff try to make out they know my son better than me.

Any advice on what i can do about this would be greatly appreiciated as it has gone on for years and it is so tiring trying to explain that they are doing wrong and why.

Many Thanks.