Ongoing Dishonest and *********** service

I have had ongoing problems with vodacom charging me double more than once with no proof and no one competent to assist me in this regard. When it happened a while back I eventually got a hold of a manager (took me months and wasted my time) who admitted there was a mistake and rectified it. The same thing has just happened again and I had to pay double because they cut me off and said I would remain cut off. It has been months again and no one has got back to me or assisted me. The service is *********** and pathetic. I have requested on numerous occasions that someone senior in the accounts or collections dpt contact me to explain - no one has. I have no problem paying what I owe but I do have a problem being de*****ed.