Slow viber service and ***** of data and airtime loosing it at the end of the month

The viber line is very poor the last 2 weeks, I pay for 20 meg line but my service is slow and of for nothing. I believe that I pay more than enough and requir better service from them. I also believe that all the consumers are being ********** with this poor service and what is this with losing your data or airtime at the end of the month, this if ***** I paid for that data and airtime but vodacom just rip me of and all other consumers. This is not legal it is *****