********** TRANSACTIONS on my account

For the past two months ********** transactions have been billed to my account. I have phoned collections numerous times, and many promises of a resolve and call back. But nothing!!!!In the meantime my account shows a gigantic arrears amount, which no can trace the source off??This may show on my credit record, and I am tired of using my time to try and sort this out, or get some answers. Vodacom has lost my vote of confidence completely,!!