Changed to contract without my permission

This is a shame i just called your call center because i had my prepaid and very happy with vodacom then you decided to tak over md change my sim to a contact with ur stuppid R60 monthly which is useless now that my sim its damaged i cant even do a sim swop i called vodacom and they adviced me to contact you *** so that i can get an authorisation letter for me to do a sim swop now what a long process with so many road blocks and curves! i called your call center nd they still telling me to buy a contract sim card from game then call back again what a shame i curse the day you change my number to contract without my permission now i want to cancel this contract i want my number back to normal prepaid i was very happy without you intruding. ***