I tried to upgrade my license. But your system (or Freemius) keeps telling me my card number is incorrect. It's not, I use it daily. Same issue when I use other cards.
Trying with Paypal also does not work. It sends me to my paypal account where I can approve everything. But upon returning and clicking the final blue approval button on your site, nothing happens. All actionable buttons disappear from the freemius popup (only thing clickable is the closing x button from the popup).
I've tried all the above multiple times (including logging out and in again). Same problems every time.