Box fried tv HDMI ports

Contour box took a **. HDMI cable and HDMI ports on TV no longer work. Believe it was an arc from the box to the. Since the tv works just the hdmi ports don't, and the HDMI cable no longer work. In my option based on the fact that my occupation involves electrical.i am putting the fault on the contour box. Is there a way to prove that? And is there anything Cox would do to rectify the problem.I did however already turn in the box and got a new one.