Yep, I've had that. Dead as a dodo, no response when plugging in to power or PC. After a few days I plugged it in and it sprang back to life. Kept happening though which was maddening. Changed batteries and still did it so who knows. Luckily contract ran out so have another one but I never got to the bottom of it. The repair centre was useless and no Apple store for miles around.
This happened to me before. I was convinced my phone had died because I looked up how to reset an iphone 7 and know it worked before and was in a right mood. Someone asked me if I had tried resetting it and I snapped "Yes, I'm not stupid, thank you".
I don't have an iphone 7. I have an iphone 6 and was following the wrong instructions.