Careful. That letter looks like spam from Nadeo. You really should reword it so it's obvious you're a fan, and NOT some slimy marketer.

Worst part is not knowing if my card is being rejected because their system has failed, or if my card has been marked as fraud for failing on their system so many times.

They need to get with the 21st century and use a payment processor on a cloud. Take the virtual payment network down, beef up the resources, then bring it back up. 10-60 minute thing. I've done this several times.

Nope, not the only one. My Visa just got rejected, too.