Telkom Billing Increase

It is actually more a question at this stage. Entered a 2 year contract for Fibre at my private house. Less than a year into the contract, they increased the price by 12,5%. When I queried this they said it was in the contract. I could not find it in the contract I signed, but there is a reference to there T&Cs on their web site. I tried a couple of times, but cannot get into the site. My question, what is the use of a contract if the rules only apply to one party? I cannot change any terms of the contract, but they can. Is this reasonable & fair