Paying for something and not getting it

I am with telkom for a few years now and it have not been a good road until now.

I want to know i can i pay for a line rental for the speed of 8meg and only getting 4meg for the last 4 to 5 months and you guys do not pick it up or just dont care and every time i phone in you tell me on your side everthing is fine i need to speak to MWEB.

I want to know what is going to happen with the MONEY i paid and only getting HALF of what i pad for i think that is robbing people right?????