Cell C is terrible with Customer Care

My 24 month internet contract expired in Dec 2014. In Jan 2015 I was billed over R300 after paying R99 for the contract I had. When I contacted Cell C they said that normal rates apply after the 24 month contract. I Requested my contract to see if this was explained to me and that i signed to aknowledge this. I was told that they do not have this contract anymore. How convenient is this?My point is how can you charge your customer in month 25 if you had a 24 month contract??? Hope that everyone is aware of this. We are currently 3 months down the line and still awaiting feedback. Terrible Service!!!!