Hi,
PO's are not released- its standard behavior , you cannot carry our goods receipt or invoice receipt for those PO's!
Your thread subject - PO's release being reversed /not acknowledged => Just check who rejected PO release and how you want acknowledge?
Do you have workflow design on PO release/PO release reject, so that a mail will be send to PO creator?
In your case,If PO release reversed- you can request releaser who assigned for particular release code, can release that PO.
Regards,
Biju K