CELL C- Customer Service- There is no such thing!!

I tookout a data contract in March 2016: ********** ********** 344552 cell number ********** 491 paying R99 p/m for 5 Gb day/15 G night. In March this year Cell C called me saying I had to upgrade as this was a special price then, had to upgrade to pay R199 p/m but would then receive 10G day/10G night. I said that was ok as I at least received more Gig in the day then, so would pay double then. They sent me the quote on the 7 March which stated that for R199 I would only now get 5G in the day?? I have since then sent countless emails - incident 180 ********** 59 this NO RESPONSE. I am still only getting 5G monthly for R199 p/m- what a ripoff!!! They either give me what they promised AND backdate it or cancel this contract and refund me since March.