Pathetic Service for 5 months no resolution

I am currently under debt review with Debt Busters. I have an overdraft with FNB which Debt busters have been paying over to FNB every after deducting the contributions from me. Not in January I find out that the overdraft has NOT been receiving any money due to the the fact that whatever was paid over by Debt Busters to FNB went into my savings account that I still had at the time which meant the overdraft was not getting any payment therefore interest accumulated. This was never gonna be picked up if it wasn't for me checking. Fast forward. FNB has taken all that credit that was lying in my savings account about R15K however the interest that's been accumulating in the overdraft due to no monies rec4eived because FNB and Debt Busters messed this account up. I have been sent from pillar to post been communicating with Abdular since May 2022 who told me there is a backlog and they needed to manually calculate the interest that was accumulated and reverse it.

Can someone competent assist me with this?