contract value changes by the month

I have vodacom Smart+ contract for R358.50 which i took out August 2017. Now the same contract has gone up to R407.71, Understandably, 1 Vat increase would take me to R360.70 but not to R407.71.

This is not the first time that vodacom tries to rip me off. The did it previously debiting me 2 times and I had to pay R100 penalty. I save every month for this phone and yet they come and ***** my hard earned money.

SIES vodacom....you *****ing my money...i only have enough at the end of the moth in my saving account and you use you "evil" accounting method to charge me more so that you can earn an extra R100

I WILL NOT PAY YOU THESE MONIES EXCEPT WHAT I OWE YOU!!!!!!!!