bridge of contract

I have contract with Cell C. I have been billed the contract amounts up to<br> untill this month were the amount went up by R10.<br> I was always paying R329 per month for samsung s3, now it has changed to R339 per<br> month. When I call them they say its \terms and condition of the contract".<br> When I ask which clause on the contract they could not explain. To me Cell<br> C is practising unfair competition to other service providers. They advertise<br> R329 X 24 and to me this should remain like this for the duration of the<br> contract. They cannot change this amount other than the bridge of the contract.<br> This amount is the amount that I have signed for not the other way around. I warn CellC customers to never take Contract with them because they can<br> change the contract amount any time as they pleased. Other service providers the<br> contract amount remain like that for the duration of the contract. I will never<br> ever take cell C contract again for the remaining of my life."""