Is a once truly "saved" Christian who has become a horrible backslider still "saved" and getting into heaven?

Your church was wrong, only God knows whos getting into heaven, because only God knows your heart and man has absolutely no right to judge who is or who is not Christian! Start reading the King James version of the Holy Bible on a regular basis and remember, Jesus was the only perfect person, no one else can, nor ever will be, even after they are saved!