Contact Scirra support by sending them an e-mail to email@example.com
Make sure you send your account info of both Scirra and Steam so they can check and give you the badge.
Also, I didn't had to do this, but placing a proof that you bought it will help you alot too!
FYI: Your signature link is broken, you can fix that by placing a ] before the , and place something between the ][ to make it as a text. Like this! Space Resistance!