Cell C ******** you with ******** Debit Orders

I’ve recently discovered that I have a 2 year contract with Cell C, however, I have not entered into a contract, not signed anything, nor am I using any airtime or data. Surely this is against the law???? It is billed via debit order. I did have a contract with Cell C many years ago. This is ********* business practice and needs to be reported. How do I get out of this contract & how do I get my money back? It seems like I’ve been billed for years…ever since I had a contract YEARS ago. The initial contract came to an end and, without me knowing, I’ve been entered into new contracts with monthly Debit Orders going off my account. Plse be aware of these ********!