Price increase without my agreement.

Hi I moved house in October and you fitted my broadband a month later carrying on my contract with you from my previous address. You are now trying to charge me £60 when I only paid £35.90 before. I have cancelled my direct debit as I refuse to pay that much when you haven’t even discussed this me me. I have tried to contact you but cannot speak to anyone until I pay the outstanding bill. I paid £69 yesterday much to my disgust but will not pay the rest until I speak to someone and they can explain why the amount has nearly doubled for the same product. I am extremely frustrated and disappointed with your service