Complain

I opened a contract for an iphone 7 and some how they made a mistake and I started getting invoice with crazy amount and no one is able to tell me what happened and the only thing they can tell me is they opened a query since they know it's mistake. But the query doesn't have a reference no for me to track it. This is affecting my credit profile because I have to reverse the money deducted from my account because is not the right amount and I get charged penalties for that. It also affects some of my debit orders and I ended up paying my son school fees very late. This is very incompetence from Telkom employees (Sandton/Mall Of Africa stores) no one is willing to help me