3 contract, 3 cancelations.. all 3 cancelations not processed correctly

Due to Vodacoms *********** service a am canceling all my Vodacom contracts. Every time I cancel a contract Vodocom keeps on debiting my account after the date of cancelation. How difficult can it be to properly cancel a contract? Well its impossible with vodacom! Ons 27 May I gave 30 days notice on my contract (cancellation ref ***). I was suppose to pa my last installement end of June. Today I received my july billing and guess what Vodacom is still billing me for that number. Vodacom clearly does not understan or cannot count 30 days. It is also umpossible to reach the cancellatio department... obviously because i am not the only person that has trouble with cancelations. Reverse the installed as I will not hesitate to take this further if you debit my account at month end. 3 contract and 3 time you do not process the cancellation correctly, I have had enough!