I’m ready to end my contact with Telkom SA

Telkom SA wrongfully charged me and I've had enough now because each year I have to deal with amounts that I don't understand and I feel like I’m being ******. TelkomSA has wrongfully charged me R202.70 for order rejection fees that I am not liable for (adding to R591.70 for 31 January) and added these into my Telkom account *** while it was debited on 31st of December, right on time. They are also in breach of the contractual agreement to debit my bank account on the 31st of each month and if the 31st falls on a weekend or public holiday, to then debit on the next working day, causing me to pay for arrears that I was not liable for when they add collection charges into my account wrongfully.