What....da hell?
I had $110 in credit at Amazon and tried to apply it to my Bomberman order yesterday, only to have that bump back the delivery date (ended up canceling that order). I wanted to use some of the credit on my Switch, too, but didn't update my order as the CS rep said it could mess with my hardware preorder delivery like it did with Bomberman.
Well, now I went into my account and my credit is... gone. Whaaaaaaaaat? I check my orders and it appears my Switch is "preparing" and the system automatically applied the credit to that order. I mean, on one hand, that's what I wanted and that's cool, but on the other hand, Amazon seems to be going full honey badger the past few days and I don't really know what to expect.
Maybe a preference somewhere? I know on their subscribe & save orders there is an option to apply any available gift-cards to the order once it ships. Didn't think they did that for regular orders though. Glad it worked out for you.