FNB *******ly deduct home loan payment and refuses to account therefor

In two day's time it would be a year since FNB *******ly deducted a whole home loan payment from my account. The amount was not due to them and in addition thereto, they raised the amount allegedly due to them without being able to provide any statements reflecting how this amount is calculated. They are unable to account for this and just ignore my correspondence. I've made two formal complaints and referred it to the banking ombud. FNB just keeps insisting that the matter has been resolved and for some strange reason the ombud just accepts this without any further input from my side. I am highly frustrated by this and the amount due to me is excessive. I am especially unhappy as the money has been due to me for the whole lock down period and I am a single mother. FNB seems to have no regard or simpathy for this. I really resent doing business with them