Invoiced double amount

I am unhappy with the service I received from Vodacom Fiber team, when I app**** for my package the consultants advised me that I will not be charged for the 1st month on both packages, they told me it is free for the 1st month. I received my invoice with a double charge and I phoned to inquire about the incorrectly charged invoice and they told me there is a pro-rota fee that I must pay from activation day. My question to them was how do I get charged a pro-rata fee if it was free for a month, the consultant I spoke to mentioned that it's only free if you get activated beginning of the month which was not mentioned when I initially took the contract. I advised the consultant that I was disputing the invoice and he asked me write an email which I did after I spoke to him and that was on the 9th of February. To date my service request has been pended and I was only told that they are waiting for credit approval via email, the person assigned to my request did not even bother to pick up the phone to explain how long it's going to take to get my problem resolved. They have already debited the amount that I was incorrectly invoiced and I am highly disappointed with this kind of service!