Terrible Service from Rain South Africa

I am currently paying for a 100mbs line and achieving speeds of between 3 and 30mbs. when i contacted a consultant, she told me that it is not possible to receive speeds of 100mbs as this is not how things work. According to her, if we get speeds of up to 30mbs we should be happy as that's average speeds for that particular line. I have logged numerous calls over the last months to no avail. I always get told someone would call me back, which not to my surprise never happened. Also with regard to the calls, the average wait time is anything up to 10 minutes with no definite assistance. How hard is it to get someone to assist? This has been going on for months with no resolution.