Cell C increase contractual prices

I have a CELL C contract for almost two years. I have a contract 400 which used to cost R470 per month.<br> Cell C decided to increase the fees to R510 per month without notifying me.<br> <br> I have lodged a complaint at their support and they rep**** stating that they are well within their rights to increase the contractual monthly amount.<br> They also indicated they have sent me a email stating that the amount will be increased, but have received none.<br> I requested my contract to be downgraded to ensure i stay within my monthly budget, but they said there is a penalty when i want to downgrade my contract.<br> <br> I dont see how they are allowed to increase the monthly fees but i am not allowed to downgrade my contract without any penalties.<br> <br> I have copied the email from Cell C and added it below:<br> <br> On 6 Apr 2015 14:05, wrote:<br> <br> \We are entitled on written notice to you (done on 06/02/15) to change the terms and conditions of this agreement if necessary because of any new and/or amended law