Customer protection Act violation - new contract

I went to the Telkom store the Sunday after that line was installed on the Saturday to change my contract from the R499 20G to the R399 10G package before it was activated and I have to date not receive any confirmation if this was done . <br> We were also advice on this contract when we exceed the limit we will not be able to continue with data usage until it recharged the next month. So we will not be able to exceed the limit of 10/20 gigs and therefore will not pay anything additional<br> I received my first invoice and it exceeded the amount I was expecting x3 <br> When I called to query this, the voice prompt advised that my line has been suspended. <br> I need urgent feedback as I signed for a specific contract and was billed something more <br>