iPhone 6 screen turns black & unresponsive

iPhone 6 screen suddenly turns black and does not respond, the power button and volume control are also unresponsive. Apple technical support solution after running diagnostics was to restore. On iOS 9.02; 64 GB, no damage to phone. I regularly reset my network settings and power down my phone. This would be the 5th restore of my iPhone 6 and my 4th replacement at the Genius bar. I'm not thrilled to get a "new" phone- the work of restoring is it tedious and time consuming, and some, but not all of my data is always lost. I am about ready to try an an Android phone, not excited w/the idea, but I need a reliable phone that works.