Cell c stole my data

Good morning, on the 4th of July 2017 I went to cell c store to buy 100gb for my wi-fi router data they gave loaded 25gb instead and I paid R1500.00 for 100gb I wasn't aware only found out last month, then I went to cell c store they checked and told me it was a mistake and it will be resolved within 48hours.they called the customer care and agreed it's thier mistake it's been a month now still waiting for the matter to be resolved.now I'm stucked with no data because now thier 25gb has been depleted.i am very disappointed in the customer service they giving to us.