Billed while I do not have a contract with them

Cell C have been billing since August 2018 and I have been reversing the debit orders because I do not have a contract with them, when their agent contacted me, they told me that I was billed because their system says I have a contract with them and it could possibly be *****, the only way to close the issue is to go to the nearest branch and submit my proof of residence, Certified copy of ID and affidavit. I submitted all the documents on the 6th of November 2018, even today (16 January 2016) I get billed monthly , Sometimes I get billed more than once every month, which doesn't make sense to me.