Attempting to purchase CSC with a Visa debit gift card. I have verified funds availability on the card, but the site doesn't seem to want to take my money. Is this a glitch or is Subeta no longer accepting gift cards as a payment method?

I don't think that's a thing anymore I think it only accepts Stripe and PayPal otherwise best to make a ticket

You can still pay via the old CSC purchase option - https://subeta.net/payments.php

At some point that page will stop working tho (Unless the made the change and didn't announce it and thats why your getting an error?) and you'll have to use the new one - https://auth.subeta.net/shop/credits