Unhappy

Vodacom has not been sending me any invoices for the last couple of months. I have previously on various occasions asked for this to be rectified. The result is now that I cannot budget for the correct amount to be deducted from my bank account. I have been told that my account is in arrears. Made a payment this morning and phoned in to make arrangements for the outstanding amount to be paid and was told that they cannot see any outstanding amounts. I requested a statement on 08/06/2015 when I had the same issue and there were months were two payments were deducted from my account 24 hours apart. When I queried this I was told that they will phone me back. I have no idea what is going on with my account, and I think the same goes for Vodacom. They could not even pick up my account number this morning - according to the system it does not exist (I quoted it like it was printed on the last invoice I received). I am very unhappy with the service for the prices I have to pay.