Pathetic customer service

I have 2 mobile contracts with Telkom and have recently just taken out the 3rd. Despite my pathetic service from the 1st contract I was still stupid to go ahead twice more and take another 2. I have just received my invoice for the end of June stating my total for just one contract is R2000+ when the package deal alone is only R269. I understand I have made billable calls where as per the invoice is R150. I have called your call center where the agent (Who's name I couldnt quiet catch) advised me that I was in areas of R900 (which mind you was just a week late and later was paid in full) and R200+ was added as interest resulting in an additional R1157.28 to my bill. So where's the money that I paid? The funny thing is when I tried asking that question to her she tells me to keep quiet and let her speak after she speaks I tell her I don't like the manner in which she is speaking to me adlnd she further blames me for using vulgar languages on the call. The nerve of blaming on a recorded line. When I told her the call is recorded how could she accuse me she tells me drop the call and call back and ask to get a copy of the recording. When I asked for a manager she says she can't put me through one as her manager just stepped out. I told I'll hold until she gets me one (they are not allowed to work unsupervised right?) I was placed on hold for more than 20 minutes and then taken out of a music hold and placed on a silent hold immediately without any communication... 1stly I'm ****ed that I was accused. 2ndly you treat me as if I'm not a valued customer. 3rdly this is a ****** problem every single month. Every single month I call. Every single month there is a problem which no one is able to help and today I get accused. Telkom. Please. This is now a HUGE problem. If this matter is not resolved I am going further.