Mweb breaches agreement!

M web's breach of charge rate agreement, regardles of the 1 year contract with mweb. I entered into an agreement wit mweb in that I will be charged 579.00 monthly for one year and in return mweb will supply and install the required router. The understanding is that if I cancel this service before the end of this agreement, mweb will charge me for the supply and installation of the said router. Mweb has now increased the above charges to 629.00 well into this agreement, siting increases by vooma (the cable articulation contractor). To my understanding, an agreement is binding on both parties and mweb can't have it both ways, it therefore unfair and unreasonable that this should take place.