Try calling your bank and asking if their fraud prevention is causing the issue. I run into similar errors from time to time trying to buy from lesser-known ecommerce sites, and my bank sometimes blocks the transactions without actually contacting me about it.
For what it's worth, turn off recurring billing before you redeem a code. I just redeemed five codes in a row, and each time they gave me a free month because I let them turn on recurring billing, then immediately turned it off. In total I got 20 months for like $50.
Is this really a deal considering MSRP for the console is $299.99?
I was able to buy one at Target a few months ago. I figured it was just old stock from when Animal Crossing came out, but the employee told me they still get one or two of them in with every console shipment.