Debit order reversals/rejections

I am feeling rather despondent after the numerous back and forth phone calls and emails with both TFG and my bank. I have recently changed my bank account from which my TFG debit order goes off (i.e. ABSA to Standard bank). I have completed the TFG debit order form correctly (confirmed with numerous call centre agents). However, my debit orders have now reversed or been rejected twice. I have inquired of TFG why this is the case and keep being referred to my bank since TFG apparently doesnt have the authority to reverse debit orders. I have called my bank numerous times and they have confirmed that no attempt has been made by TFG to collect the debit order and that this is evident by the fact that the debit order and reversal is not reflecting on my bank account/statement. The bank has also confirmed that no debi check was in place since I suspected that I may have rejected the debit order by mistake. I have also had more than sufficient funds in my account on both debit order days. I have a 6 month interest free TFG account which has now accrued interest for the days that my debit order has been outstanding. The interest in quantum is small but it is the principle of potentially being unfairly charged that doesn't sit well with me. I have seen a similar issue raised on this platform and would just like to know how it was resolved. Please do not refer me to the customer services department. Heaven knows I have heard enough of nothing from there. Also, not collections or the debit order department who only operates via email. I am rather convinced that TFG is at fault since my bank has confirmed that if a debit order is reversed/rejected it will reflect on my bank account statement as an in and out. This is however not the case. This platform seems to be my last hope of getting some form of an answer. Hereafter I would in all likehood settle my outstanding balance excluding the interest charges since TFG cannot seem to give me an answer. Quite disappointing for a large listed company.