No one can explain my bill for the past two months

My Contract bill has increased in a mere two months with no explanation. When I call the call center no one gives me an explanation as to why my bill is so high I get different answers all the time. in the month of August I switched to international roaming for 4 days and changed back on the normal network on the 21 of August after I saw the debit order of R1600 in which I queried and they confirmed it was for the month of August which included the roaming, however this month my bill came up too R2000 and when I queried the bill they claim that I called in and upgraded to limitless calls in which I didn't. in the month of May or June I called in to change the monthly limit from my one number R50 to R150 and the other numbers monthly spending from R100 to R150 now all of a sudden my bill has sky rocketed in a mere two months. The one lady who was very rude told me that I had R300 worth of calls that I made to telkom calls in which with their promotion is free the first year of signing up with the contract, and they require that you pay an additional R99 if you want to continue with those benefits. which I did not agree too. I want Telkom to give me a breakdown of all these costs