blue, black and white screens after ios 9 updated

I recently updated my iphone 5S to the latest 9.02 update and had problems with the phone's signal strength, been a week now, last evening the phone's screen just blinked blue for a bit and restarted; this happened for a number of times. There after I restored the phone to factory settings and it seemed okay for a few hours, but the issue only worsened with the screen now turning black and completely white at times and just restarting.

So basically, Im left with a bricked phone.

PLEASE HELP !!!

PS i have never jail broken my phone-EVER.

Thanks in anticipation ...