Iphone 7 plus won't start after a fall

So I was in a call when the iPhone suddenly slipped and fell on the ground. Mind you it is well protected by an UAG cover so there was no apparent physical damage. However I noticed the phone had turned off. When I restarted it, it said 1% percent battery which was odd because it was having at least 50% charge. A while later I put it on charge to get the battery up.

Now it won't turn on. The apple logo keeps coming on and off but the phone just won't switch on...like the Apple logo comes on for a few secs then goes off and it has been doing this for the last hour.

I tried doing a hard reset, connecting it to my laptop but the same thing keeps happening. Any idea what's going on and how to fix it?