Telkom doesn't deduct my monthly premiums yet funds are in my bank account. I get charged for late payments when it's 5th their fault

I have a Telkom router which is on contract I pay month to month via debit order which is R140pm. Which I purchased last year April 2018 on a Easter special. As of lately Telkom doesn't debit my bank account for their monthly premium when there are funds in my bank account. I have been getting charged late payment charges which the fault is with them. I have queryed it so many times why do they not deduct frm my account when they have my banking details. They wait 2 send me a new statement with extra charges for the next month yet its their fault they don't debit my account. I called them at 9am 30/09 and practically begged them can you please debit the amount due for month end September. They said by the end of business they will. I am checking my debit orders this morning and all my debits went off expect for Telkom. They will issue me an October statement reflecting no payments done for August and September yet the funds are in my bank account waiting on them. I spoke 2 a lady called dineo through their call center in August who assured me end of September Telkom will debit. They didn't again I went into arrears because of Telkom and gave me a bad record. I spoke 2 a kathlego yesterday 30/09 who said the very same thing that Telkom will deduct at the end of business. It's 01/10/2019 and once again Telkom has not sticked to our agreement of deducting the funds. My installment should be R140pm but come month end October it will be a bill shooting over the roof. The agents logged emails for me yet no one has ever gotten back to me about my query. Why doesn't Telkom bill my account and advised me they are no funds in my bank account when the funds are sitting there waiting to be deducted. I honeslty don't know what to do now. I am so exhausted about querying the same simple thing. I am not refusing to pay these amounts which are extra which is a Telkom error. I want 2 maintain a good credit score but I can't because Telkom does this to me month in and out... Can i please get assisted on a simple query.