Can no longer buy ANY backward compatible games on Xbox One or the web

Well I have contacted support three times and still no resolution. I can’t find anything that has helped. Can’t believe after buying BC games through my Xbox One console and xbox.com for years that all of a sudden I loose the function with no explaination....giving
it a few more days before I call it quits. I would hate to give up after having every Xbox console and enjoying them all but if I can’t use one of the main selling points (BC) then I’m done I guess.

Well just tried that and still no luck. I will see if support reaches out to me. The person I chatted with yesterday sent it down the line I guess. I'm not so worried about not getting that Castlevania game, but not being able to get any BC games.

I have bought many Xbox 360 and original Xbox games either from my Xbox One or through xbox.com. Now all of a sudden, I get "No payment on file". When I click on change payment I get another error saying oops, you found a glitch. I am still waiting
for support to reach back out to me but so far, they have not been helpful. Anyone have the same issue and found a resolution? Support mentioned using a Xbox 360 but I don't have one.

You said you clicked on "change payment", can you instead try and add another payment option such as paypal or another credit card?

https://account.microsoft.com/billing/payments/?ref=sfcBillingPayment

Could be that your payment option had expired?

I too have received a similar error(no valid payment on file) when trying to claim Xbox360 Games with Gold, not recently but several months ago.

I'm not sure what the cause of the issue is, but this has worked for me in the past:

I removed my payment options and did a reset. Then re-added my payment options.