Q: iPhone 5s won't switch on or charge.

Your iPhone needs a new battery.

You can make an appointment at an Apple Store Genius Bar > http://www.apple.com/retail/geniusbar/

Or send it to Apple for service > iPhone Repair - Official Apple Support

Try resetting your iPhone and then check whether it gets charged properly. To reset the phone, press and hold both the Home button. If that doesn't fix the issue, the best option is to contact Apple Technical Support Team via phone support team. You can locate the phone number on the link below.

Contact Apple for support and service - Apple Support

hey I dont know much but this site claims to https://www.mendmyi.com/blog/2014/06/has-your-iphone-5-died-and-wont-charge-or-c ome-back-on-we-can-fix-that/

Hi

Follow the instructions here:

If your iPhone, iPad, or iPod touch won't turn on - Apple Support

Sorry for the delay, Ben. Yes, even I have read about U2 IC chip which could be cause of this issue. If your iphone is still under warranty, I would recommend you to contact Technical Team. If you have any queries, please do ask.

Thanks.