Useless Vodacom *****ing money

Useless Vodacom I have 2 contracts I moved my payment date from the 1st of the month to the 7th of the month now they charge my a double payment, for what reason? Just because I want my payment moved to the 7th of every month like I stipulated in the contract I want it the 7th but no useless Vodacom moved it by themselves to the 1st now if it bounces I pay a fine of R100 fair enough I moved it so it corresponds with my salary now I get charged double payments... I had to pay 3times in March. Would not recommend Vodacom to anyone they just *****ing money and BTW I have a unexplained R10 added to my bill every month if you count everything together on the statement it comes to a specific amount with vat and everything but if you check the total it has R10 extra?? They can't count now? Useless company