Not happy with telkom

I have a contract with telkom of 80GB data for R149. 99 a month and that lasted me the whole month. I started experiencing problems with my data during November it wouldn't even last two weeks then it finished. Today it's the first of April and my data is 60GB instead of 80GB I have layed a complain before and I was never taken seriously because till today I never got a response from telkom. So it's either they cancel my contract or give me my 80GB as per contract. I can not pay for data and also top it up no way that's day light *******. I have had enough!!!!!!