I am receiving an outstanding bill that was never even mine!

I am not sure what to do but, I just received an outstanding bill from collections for an account I never even had. I just received a letter that says it’s reflecting negatively on my credit report. I recently left college and I am trying to work my way out of this financially straining COVID crisis and now I am being charged for an outstanding bill that isn’t even mine. What can I do to dispute this?