No answer at call centre and high bill

I have been trying to get hold of someone at the call centre for 2 weeks now with no luck. If I phone a branch they say the only way they can help me is if I come in to the branch. Unfortunately I don't have the luxury of time to go and sit at branch for hours. My bill was very high for April, I did not use more data or make more calls than normal. No one can help me!!! We also have very bad signal at home, someone promised us that they would come and install a booster, it has been months with no luck. They know you can't cancel your contract for 2 years, so they just don't care. There should be something protecting us against these things. Anyone???