Hello,
Thank you for contacting Rank Math and bringing your concern to our attention.
It seems you already have used 20 credits on your site, thus you’ve 35 credits left. We provide 5 credits free for the FREE version of Rank Math and since you’ve purchased 50 more credits, you basically had 50 + 5 = 55 credits.
Here you can see the Used (20) /Total Credit (55) count:

Hope that helps, and please do not hesitate to let us know if you need our assistance with anything else.
But I’m not on free version. I’m on pro version.
I used all that was available to me. This morning I decided to buy 50 credits, then I only see 35 loaded. I think it’s a mistake.
Hello,
The current account you used to open this ticket is a free Rank Math account. It seems like you purchased the plugin with some other email address.
Can you please search and forward a receipt from FastSpring.com so we can locate your account?
Looking forward to helping you.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.