Poor communication and incorrect billing

Last year July I took a contract with Telkom for fiber/wifi and I was paying R549 and all of a sudden I am being billed R619 without any communication. When I enquire, I am being send from pillar to post. I spoke to 3 different consultants and the 1st consultant says it’s because my upload/download speed was increased and she referred me to sales and the sales person says nothing has changed on my upload/download speed and the 3rd consultant says Telkom is increasing its prices ever year in April. Yet when you call them there’s a voice over that is saying Telkom has increased the speed of download/ upload at NO extra cost but i am being charged for that.