My bill suddenly went from R425 to R555 this month

My bill suddenly went from R425 to R555 this month. I called the contact centre yesterday to try and get clarification on this, after holding for 6 minutes, finally a consultant took my call, but to my disappointment his line disconnected before my issue was resolved, I hoped he would call me back as it would seem his line was the one with the problem, but unfortunately that did not happen, I could not call back as I knew I would have to hold for a long time, so I sent an email regarding this matter, so far I have not received feedback. I did go and make a payment because I was worried my services would be disconnected. My worry is when checking the balance for next month, it is sitting at R526 which I still don't understand how it came to that amount.