What do I do if it's not accepting my card payment at checkout? I have money, triple checked the info, still not taking my only card. I don't have Apple Pay

If you still experience the issue, please call Customer Service and tell them you have a "block payment issues, possibly due to billing or an invalid license" and the agent should be able to help you. Here is how you reach customer service:  Turbo Tax Customer Service 

The department that handles billing is located in Mountain Time Zone.  You need to call Monday-Friday between 9:00 AM and 4:00 PM Mountain Time.  It is only department that can help with that issue.