Unacceptable behavior

I am their client from 2014, I didn't get quality services, i phoned to cancel, I was assured that the contract will be cancelled. I realised deductions, I went to my bank to reverse and cancel the debit order. I was immediately phoned by the collection department to say I am owing, I tried to explain, but my explanation was not accepted, I was just told to pay the money and i was assured again that my debit order will be cancelled. Im surprised to be informed that i owe again. I was Netstar client since 2014, I never enjoyed any benefits.