non disclosure on product sold

Sometime in September I went to a Cell C in Jabulani Mall and took out a contract for a 5 GIG router. I was told the pricing option will be R99.99. I was so excited to sign up with the service provider because of their low rates. I was never told or even given an option to choose the data plan. I was surprised on the 21/10/2015 a debit of R1916.18 going off from my account.I went to the outlet the following morning to inquire and they just gave me a statement and told me this amount was for my data usage. I was then surprised again when I received a statement for November still billing me a ridiculous amount of R2245.71 while I made sure I was not surfing the net as much, I went back to the provider to inquire and was told that I was on a R2000.00 data plan which I had not agreed upon and plus this is more than what my salary can cover and I believe as a rational person I would not have agreed to this. what I found strange was that the Owner Saspri said I could not be assisted, they did not want to take responsibility. I am unhappy with CELLC as a service provider that they would dismiss my query without logging a complain or following any kind of process to resolve the matter