Okay, so here is what I just did to help you gain access to your account.
1. I unbound the Steam and Google accounts from Szplit123
2. I sent a password reset to the email bound to Szplit
So you'll have to reset the password for the Szplit account (because it's no longer tied to either Steam or Google). Once reset, bind your Google and/or Steam account to it. Once you've done that, you should be able to log into it with either of them.
If you have any problems, feel free and let us know.