If you are facing issues due to the wrong billing status of either Sales Documents or Deliveries, there are reports to help you correct this.
Report SDVBUK00
The SDVBUK00 report can correct VBUP-FKSAA of Sales Documents.
It calls RV_XVBUP_MAINTAIN.
Report RVDELSTA
The RVDELSTA report can correct VBUP-FKSTA of Deliveries.
It calls LIPS_STATUS_MAINTAIN.
As you can see in the screenshots, both of these reports can be run in Simulation mode.
The billing status is redetermined based on the actual value of VBAP-FKREL for sales documents and LIPS-FKREL for deliveries. And also on the item document flow in table VBFA.
If VBAP-FKREL or LIPS-FKREL are wrong, then you will need to adjust them before, like mentioned here: Billing Relevance
If the document flow table VBFA is wrong, then it is also necessary to adjust if before. Unfortunately, there is no correction report available for VBFA. There are however some notes containing correction reports to repair specific inconsistencies.