Sadly, you can't do anything at this point if you don't have access to the Lobstr vault app. If you don't have access to the signer that was set in your account then your account is lost.
NOTE: Do not accept private help for this, NO ONE can help you if you don't have access to the second signer that was set into your account. Some scammers take advantage of this and try to steal/charge your others accounts promising that they can do something for you
