Boy are VISA rules fun.

Am I understanding correctly that if our customer orders merchandise online and does not receive it:
1. This is not an error under REG E, so REG E does not apply
2. We assist the customer by doing a merchant chargeback
3. We only have to do provisional credit for unauthorized transactions, therefore not in this case

If this is not correct, could I get an assist to find where in the Visa rules it says I have to give provisional credit?

You are mostly correct.

1) Yes, for debit cards. No, for credit cards (Reg Z).
2) Yes
3) No. Visa Core Rules Section 1.11.1.2

Thank you, that helps.