Can you buy microsoft points online with an american express gift card?

I have a $25 American Express “Amex” gift card that I want to use to order 1600 MSP for my xbox live account. I’ve only ever ordered from xbox live itself on my xbox, through a credit card. Is there any place online that will accept one of these cards and then send you the code in the mail? I found one reputable source, but turns out they only take Mastercards and Visas.