You must make sure that the wallet address that the key has been transferred to is the same as your Fnatic ID connected wallet, if it is different, it will not show. If you need to change which wallet you’re using, then please read about changing wallets, here:
https://help.fnatic.com/support/solutions/articles/77000525718-how-do-i-change-my-wallet-

Once you’ve confirmed you can see your key on the blockchain within your wallet, you can visit the Membership area https://fnatic.com/account/membership - scroll down to the wallet area, click the “Actions :” button, then click “Refresh Wallet”.

This can take up to 24 hours, depending on how busy the Polygon network is, however it is often instant.

If you still do not see your keys after refreshing, please open a support ticket quoting your Fnatic ID username and Wallet Address.