I have a J7 Crown S767VL that has no screen display it stays black phone is still powered on and when I try to hard reset it doesn't fix the issue I have tried to power off by holding power + volume down button for 20+ seconds and after about 15 seconds of holding buttons it vibrates every 1-1.5 seconds and does not power off. I have been attempting to factory reset with black screen with no luck and have exhausted my options available online. Please give me suggestion(s) on what I can do it is a straight talk phone.