If you have a deleted batch in the invoice batch inquiry is it possible to post it or retrieve and post it?
this is in AR

No. The only module you can do that for is Ledger (at present).

If it's really large or you don't know what it consists of, your best bet is to find and restore a backup from before it was deleted. You can export from this backup and import the invoice batch into the live data, although it is not a trivial task (that's why God made consultants).

Steve