Suggest:
1# To make sure the suspected failures in your non-conformance inventory were responsed to suppliers, this is to require you & your team to item by item check these failures in your MRB stock;
2# To establish a tracking list to purchasing dept & managers, specify failure part numbers/vendor/involved quantity/failure description & root cause/what you have done with supplier/pending dept/pending who/status/so on;
3# To regularly host MRB meeting, to drive the corresponding buyers for actions and report the result to team & managers for reviewing.
Reminder, you are the owner for MRB handling & get quality agreement with supplier, but it is buyer to charge failures RMA to return back or replacement to suppliers.