I Asked to change my package to a cheaper one and I have now been stiffed for more money

My Contract came to an end in July, So I had a look and everything seemed more expensive if I renewed, I spoke to someone on the phone and as he couldn't get me anything cheaper, I decided to cancel and go with Sky instead, He then put me through to "cancelations", who didnt even let me speak before going into a sales speil to "see what he could do for me", he then came back with a cheaper package which I agreed to. I then got the contract though on email which is nowhere near the price he quoted me but is almost £25 per month more expensive, AND I apparently have a first payment of £150 to make too.

Since then I have tried to speak to someone and literally cannot get through to anyone, My landline appears to have gone off, and I canot make outgoing calls, everytime I try to call I get some robot that asks me a plethora of questions about my account and what i want, then tells me they only have 38 minutes of their shift left,  and hangs up.