Hello,
Thank you for contacting Rank Math, and sorry for any inconvenience caused.
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? You can add them to the designated sensitive data section

It is completely secure, and only our support staff has access to that section.
Thank you, and looking forward to your update.
Hello,
I have updated the sensitive data as requested. Can you please check further?
Thank you.
Hello,
It seems like you purchased the subscription using the “Business account” email address in the sensitive data section of this ticket.
The account with which you’ve posted this ticket is linked to the “Free account” email address in the sensitive data section.
Would you want us to merge the accounts for you? If so, please let us know your preferred email address and we will do the needful.
Looking forward to helping you.
Thank you.
Please merge.
My mail is c*******************@g********
Thanks.
Hello,
Thank you for your patience.
We have merged your accounts as requested.
Please check on your end if everything is working as expected.
Please go through this video tutorial that shows you how to get started with your PRO license:
Steps to be followed:
1. Ensure that you are logged in to your paid account
https://rankmath.com/my-account/edit-account/

2. Disconnect and reconnect your account from inside WordPress:

WordPress Dashboard > Rank Math > Dashboard > Help and click the connect/disconnect and then the connect button.
You will be taken to RankMath.com again where you can connect your account to activate your license.
You do not need to remove the free version of the plugin. Everything will be ported over to the PRO version.
Hope this helps.
Thank 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.