Terrible Service and Customer support

I have been receiving terrible service and line speeds from Cell C. I have the 200mb/200mb line and i have not received my 200mb in the last 6 months. i have been getting 130mb/148mb and i have multiple screenshots at different times and different dates. when logging a call with cellc fibre department they simply said well your internet is not down and you are receiving 75% of what you are paying for. in what world do you only receive 75% of what your are paying for? If i purchase 4 tyres and receive 3 that would be unacceptable. The line constantly goes down for hours and then comes back and its very slow. i would receive 130mb/50mb. This is supposed to be a 200 mbps line. This is ****ing unacceptable.