contract cancelation

Goodday my name is cathrine nkala kadiaka I have a contract with mrp mobile last month I told them I don't want the contract anymore they must terminate it ,i payed all the bills the told me to in order for me to cancel the contract they did tnt even cancell the contract now they are saying they are coming to collect the device but I paid for I don't understand and every time I call the call centre they tell me different stories,now they even blocked my number from calling the call centre, I use to speak to nerisha randhani regarding the contract via email that's before I made the payment now she is not responding to my everyday email anymore is the one who gave me the total amount n I payed everycent, so please help me