Suspected *****

I had a contract with vodacom that finished April 2018. They never notified me that the contract is about to end neither did they ask me if i would like to continue or end the contract so I kept on paying. When I eventually cancelled the cotract they changed it to prepaid and not even a month after the conversion they handed me over to debt collectors but cannot provide me with any proof as to why they handed my account over. The debt collectors cannot give me a proper reason as to why they are issuing a garnishing order so now I'm stuck in the middle because none of them can actually assist me.