Incorrect billing and poor customer service

I am due for an upgrade and they have charged me thrice the contract price without consulting me and now they seem don't care to fix it i have to wait for hours and no one picks up the call from cancelation or retention department i have tried both. seems that they don't even care about this platform either as they haven't rep**** to my previous complaint. they might be desperate for money and it appears that this is the way they want to go about.