I got the same email.
I was charged the correct amount and had confirmation my package was shipped.
My transaction is complete. If the retailer has an issue with their payment processing facility, they need to address that themselves.
Imagine getting home from Costco and getting a call from the Accounts department asking you to reverse the charges and authorise new charges through a different payment facility because they have issues with Citibank who provides them their merchant services.
*ring ring*
"Yes, hello Costco accounts.
Yes, I was at your store 4 days ago.
Huh? Citibank didn't pass on to you the full amount? But my statement says I paid in full. If you would like a copy of my evidence, I'd be happy to provide it to you so you can present it to Citibank for investigation.
No, sorry, you'll have to talk to Citibank. I have evidence to state that you were paid in full. It seems to me that yo have an issue with your merchant services provider. This, sir, is not my problem.
Good day."
*click*