Once logged into your Fnatic ID account, 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.