Sharepoint deleting data and sites

Hello, 
We have noticed an issue that started about a year ago in which data is being deleted in Sharepoint. When looking at this data in the Recycle bin, it will show it was modified/deleted by specific Users but these user deny ever doing such a thing. It is at the point in which we believe the Sharepoint system itself is actually deleting data possibly due to a bug. It would be odd for the employees tagged in the Modified By field to have deleted it. 

Our data is backed up so recovering any deleted items isn't the issue. The issue is that we are trying to get Microsoft to investigate. We have submitted tickets through the MS 365 portal but they state they only work on break/fix issues. 

Any recommendations? 
I can see searching the internet this issue has come up for many others in the past.