Telkom taking advantage of being a service provider

I have contract with telkom. It is a top up contract. My problem started in November last year when I renewed the contract. I have changed my banking details so have given the new ones. In December they did not run the debit order so I paid via EFT. January they ran a debit order in a previous bank account which was no longer in use, they charged me R200 rejection fee even when I have paid via EFT. In February I phoned them and gave them new bank details again, end of February they ran a debit order in a wrong bank account which is the previous one which was no longer in use, obviously it came back unpaid but they never charged me R200 this time. I paid the account via EFT. End of March I paid the account via EFT bacause I thought they were having some difficulties to capture my new banking details. I paid it very early on the 22nd of March. On the 25th of March they ran a debit order on the the new bank account which is FNB one, surprisingly so because when I ask them they said they never had FNB bank account they had the standard bank account which is the one which was longer in use. Since the account had been paid twice, I reversed the the debit order in order to have enough money for other debit orders, I got charged R200 rejection fee. Something I don't understand because they told me they don't have FNB account, so I'm getting charged a penalty fee for paying my account on time. They did not even border to inform that they have finally managed to capture my FNB account on their system,i must expect the debit order in it. I inquired about it but I only got "we are sorry" as usual. We work hard for this money and try by all means pay our accounts then you have service provider like Telkom just add R200 on your account as they wish, not fair.