Unilateral changes to contract

For reasons unknown to me, I have been charged an additional R99 for 120 minutes in September which I neither need nor ordered.

Further to which I was informed via sms that my current contract option with Cell C will change as of 31 October 2019. This in spite of the fact that earlier this month I was informed that I cannot upgrade until end of December 2019. To further exacerbate the situation the new plan is similar to the plan which I intended to take, except for the fact that it is far more expensive. Furthermore the new plan (of which I have been unilatery informed of) is more expensive than the plan I initially signed up for with less than half the minutes.

On top of all of this, I intially agreed to a bill limit of R550 (in writing) Cell C, R500 of which was for the contract. However Cell C has randomly increased the contract price and changed this limit to such an extent that it is now at R648.93.

I have spoken to numerous agents, most of whom just referred me to another agent.