Vodacom going down the tubes and they deserve it

After numerous enquiries to this company and hours upon hours spent on the phone to complete idiots who have not got a clue I am a step closer to getting out of Vodacom completely . I finally got a premature cancellation form which was for the duration of my contract stating it was for 4 months but they insist I will still be billed at the end of this month R608.50 !! I have paid the amount stipulated being R2167.00 with all the documentation and proof of payment to ********** . I have had NO response to tell me it was received and NO response as to why they charge me in arrears as I am charged in advance monthly . This means I will pay an extra month on the contract ie 5 months !! They are complete ******* artists and trained just to bull**** the public . This company can only carry on for so long with ******* staff and a CEO who does not give a toss .