Order placed no problems, money out of my account....

Order placed no problems, money out of my account.
Got an email from then the next morning saying that the order failed a security check, not sure why they accepted the order l but in any case they asked for me to email a bank account statement with the card number 'clearly showing' along with the address.
I explained my card number was not displayed on my statement, like all Australian banks I know there is an account number which is linked to the account which is different to the card number.

Additionally I explained that requesting a credit card number being sent via email would be in breach of PCI requirements (section 4.2 if you're curious).
The standard work around is to mask all but the last set of digits, the fact they did not ask me to do this is a clear warning sign this retailer has no interest in protecting its customers credit card information.

Either way after my email rather than reaching out to me they cancelled the order and sent an automated credit note.
My first encounter with this retailer, not the best.