LOCKPORT – A Niagara Falls woman, who allegedly confronted her former boyfriend over an unpaid cable TV bill and ended up stabbing him to death, pleaded not guilty Thursday. Chamia N. Johnson, 34, of Seventh Street, denied the charge of second-degree murder. State Supreme Court Justice Richard C. Kloch Sr. ordered Johnson held without bail, pending a pretrial conference June 9 and a tentative trial date of Sept. 19.