Poor service

My contract expired in 2015. They phoned me to upgrade on numerous occasions. Every time they said they do not have phones and are waiting for there stocks. On the 12th February 2016 a gentleman phoned me and I advised him that I want the contract cancelled. He said that he would cancel the contract. I have just phoned to advise and confirm that my contract is cancelled. I spoke to the lady and she advised me that it would only be cancelled the 2nd April 2016. I advised here that I have previously cancelled this contract but the payment is still going thru. I advised here that I am going to put stop payment on the next payment as this contract is not been renewed. She then advise me that the legal department will contact me if I put stop payment on the payment. I told here that I was adamant to put stop payment as I have gained nothing from Virgin Mobile for a year, as they could not supply met with a phone for upgrading or renewal. It is only R149 pm but the principle of the matter is they are not able to produce.