Worst service provider

I regret taking a contract with Vodacom.if there's anyway they can take back their device and leave me and my number alone I would be very happy.first of all the consultants are not helpful because they never assist but put you through from 1 department to another without fixing the problem until the call cuts and nobody calls back.I upgraded my phone and I was told i will be paying a certain amount but nope Vodacom deducts 3 times the amount.I was told a service request is put through and I will be called back and it nevertheless happened.If I don't pay my record gets spoilt so I feel bul**** and helpless.If anyone knows what I should do please assist.