Telkom has bad customer service

i took out a contract by telkom for R1099 and the first month i had to pay nearly double that amount and i understood why as it was the carry over, but after that i decided to make early payments as i get paid on the 15th of every month and the original agreement is on the 20th of every month, but to my surprise Telkom charges a fee of +-200 because i paid early and i have contacted Telkom about this and after two months of paying extra to my surprised i have found out that early payments should be made 10 days prior to agreed date, but in the store i was told differently and to me a customer i find this to be extremely ********* of them and a fail on their side by not making mention of this prior especially when i have asked the sales representative if i can pay early and all he has said was yes, Telkom should really provide there sales team with proper training and they should really upgrade their customer services as they are no help as i just want my money back. if they are trying to **** a +-400 from me how many other customers are they doing this to thinking that we all will just accept this type of behavior from them.