I also just ran out of my "free" month. First there was only an option to pay by Steam Wallet, which didn't work. I contacted support and now have an option to pay by credit card. I'm getting Error 406 - but $1 charges from SE are showing up all over my credit card account, so the card is working fine and the card info is fine. The successful $1 charges prove that.

So support told my to load Crysta. The credit card payment to Crysta gives error 401. When I use Ultimate Pay they also refuse my card. I've had my card for over 5 years and I don't want to go into details but there's well over $10k before I hit the limit. I used the card to purchase the game in the first place a month ago, and I've made multiple purchases this week.

If SE can't figure out how to accept payment through the advertised methods, I want a refund on the purchase price of the game.