BAD BAD SERVICE

My number is suspended and when I phoned in to find out why they are telling me that I have not paid and I've opted for something on the 17 November...I told the lady that I didn't but she insisted that I did... I asked for proof but she didn't have any, I also asked to speak to her supervisor but she just said he is not there then she decided to put the phone aside until it went off. I'm not happy with the service and would like the contract to be cancelled with immediate effect!!!!