Increase against contract

I received an email advising that my monthly subscription for my fiber line will go up to R709. I contacted Vodacom fiber a week ago to complaint about this as I signed for a 24 months fixed contract for R599 p.m. , the consultant advised he will log a request to escalate as I was complaining that this is against the agreement I made and received call reference SR*** and to date no one contacted me about my complaint.