Is it possible for Shedim to masquerade Bas Kols to decieve people , like making people feel that it is Bas kohl but in reality is from Shedim?
This question and answer from yeshiva.co might be of some interest to you. Basically, even if one were to accept the premise that shedim are actual, physical beings (which isn't unanimously accepted), they still don't have free will. They are required to do God's will in much the same way the Satan has no free will and can just do God's will.
In any case, the Talmud says if you don't worry about them, they can't affect you. So anybody who is on a high enough level to cause a Bat Kol to address him would presumably also be on a high enough level to not be affected by shedim.