Mtn is a ****

I took a contract with mtn which I clearly stated that i only want the data they are offering with the contract 5 months later i get a bill that i owe R8830 for the month of October and my installment is R535 which I pay every month. They are stating i used out of bundle data (10 gig). There was never any communication from mtn that they are offering those bundle and how on earth can one use that much data when i have unlimited wi-fi at home. I went to the store to follow up, i got no help. I called to follow up, still no help. MTN is a ****. ********** on a higher level. I regret taking a contract with them.