My iphone 5s won't switch on?

I need some serious help. The other day I put my phone to charge like I always do and it din't charge so I thought I would switch off the phone and charge it and it never came back on since. I took it to a phone repair store and they said it's a problem with the mother board. I have taken good care of the phone I don't know the the problem is and it's been only 2 years. Can someone please help me? I've tried restarting it, charging it for an hour, everything and nothing has worked.

Ewfefef

Not sure why you don't trust what the shop is telling you.

Age means nothing.

Try another Lightning charging cable. They have a horrible reputation for partially failing in a way which lets the phone recognise it's connected but doesn't allow it to charge.

Until the recent re-design of the Lightning cable it wasn't unusual for them to fail every few months.

Plenty of ignorant or unscrupulous repair shops diagnose a faulty MoBo after telling the customer they need the phone password and Apple ID in order to attempt a repair. Many owners then agree to leave the "near worthless spare parts" with the shop to pay for the work done diagnosing the fault and the shop then ends up with a free iPhone which they can fully resell by just adding a cheap generic Lightning cable.

Plenty of people have iPhone 5 and 6 models using the Lightning cable so it's easy to plug your phone onto their charger to see if it fixes the fault before buying a new cable. The cheap generic ones are even worse than the Apple originals and the current brand new Apple ones seem to last far better. Or just use an old reliable Thunderbolt cable and an official Apple Thunderbolt to Lighting adapter; it's ugly and bulky but does last well.

Anecdotally, many users have reported that Apple Stores will exchange faulty Lightning cables for new ones without any quibbles even if out of warranty, but if true it likely would exclude cables with obvious external physical damage. So if you live near an Apple Store and don't have to pay extra for a special trip there it's worth taking your faulty cable along and asking. Obviously it's also the ideal place to try your "faulty" phone on a known good charging cable.