iPhone X touch screen is not working

I ordered an iPhone X on 27th October 2017 from apple store to an US address (TX)

My Mother has got the phone on 24th November 2017 from a courier service and she sent it to Sri Lanka.

I got the phone on 30th Nov. and it worked really good.

Since yesterday (13th Dec) the touch screen is not working. I have to tap many times to get a single tap. Even I can't shutdown the phone.

I did the hard re-set, but couldn't work. I searched on web and I found many people have same problem.

In Sri Lanka we have Apple authorized dealers. I asked them and they said still they are not selling iPhone X and they can not replace.

Is anything can do for this, because I have spent 999$ and phone is not working.

Is apple site is responsible to replace a new one or repair it? because I directly paid the apple site.

If I send it to USA, Can I get a replacement?

If yes, from where?

Please advice me.