Billing

I took an iPhone 11 in July at istore, as a customer I know that I can afford and there will always be money in my account, end of August telkom only debited R1279 and leave the other R199.99 aside, I was soo confused and I didn’t know what was wrong, I called the call centre and I was told that their system had some errors so I need to pay cash the amount that was no debited, okay, I did that, same thing happened in September and I paid cash the amount that was not deducted, in October I got paid 5 days before month end and I decided to pay all my telkom account at once because telkom doesn’t debit my whole bill, well I got an sms saying that my account is not paid, I called in and I was advised that I was supposed to pay 10 days before my debit order date, okay I was like I will keep it that way, end of November telkom only deducted R215.00 I dunno why, tried to call them but their machine told me they are experiencing some technical difficulties, paid the amount that was not deducted, little did I know I was charged extra R201.70 for paying early, I am not going pay that because I was not told not to pay cash and again, why is telkom not deducting the full amount while I have a contract with them and why I was never told from the beginning that I will have to pay cash on some of my debit orders , my ID is *** they must call me on *** and I am not gonna pay an extra amount it was not my fault