RA's pharmacy computer is a double scan system. Errors of wrong pills are less frequent. Only way to get an error now is to key in the wrong drug in the beginning. But they even scan your hard copy so finding an error is easier. They even have a thumb print activator for IDing the pharmacist who dispensed each RX. Can't fudge that either.

CII's like yours are inventoried on the spot as each RX is filled.
It is quite difficult to scam the system now. But not impossible.

Double scan means the pharmacist checks the RX and scans in the UPC bar code from the bottle the pills came from and then scans the RX container to see if they match. Many places do this now.

I do think you were scanned at the register because the signature capture box activated. So I don't know WHAT is going on there. CVS still uses tags for signing, and WalGreen's has no capture box at all.

You could always contact your insurance to see if the claim went thru. Give it 2 weeks since the date on the RX tho to see.
That might show "something" if things are hinky there.