You may be trying to login with a different account than the one you originally used to sign up. Try to remember which one you originally used and you should be able to login with that one.
If you cannot remember which social network or email you originally used, no worries, just contact us at firstname.lastname@example.org and we will gladly look it up (after verifying your identity, of course.)
Then if you would like to link your social networks, first login to the originally used network, and then go into your Settings. Scroll down to find the social network switches (the one you just used to login should be switched On) then switch on whichever other one(s) you would like to use. That will prompt you to login to that network and that way our system will know that all of those logins are you.