Inventory Value Reconciliation Report - File corruption

Hoping someone can help with our out of Balance Inventory Value Reconciliation Report since early April'23.

Unfortunately one of our staff entered a number of Credits  against Inventory Items at this time, and this appears to have triggered incorrect Current Values of Items, and as a result the Inventory Value in this Report no longer balances with the Account Balance. Apparently credit notes corrupt the file.  While all historical Reports were balanced previously, they are now all out of balance, but the amounts they are out by, differ each month!

Unfortunately this has happened in the past, but we were able to send the file to myob and the issues were fixed..

However,  this time I have struggled to find someone in myob that can help us fix this isssue. Since April I have called myob constantly, spent hours on the phone, transferred to at least three people each time,  tried online script fixes, gone up the chain to gold level, and then only to get disconnected(even though they tell me they will call me back if this happens!) They never do!! Yesterday I was on the phone for 2 hours and when they finally asked whether our file had been restored by myob- disconnection again! 

From our previous experience myob data services requested a backup of our file, which they then restored. I have been unable to find someone to do that now.

Can anyone help with this issue. It would be greatly appreciated.

I can provide case details if required.