Green lines on the screen

I see green lines on my screen right after I updated my software. I went straight to my nearest Apple authorized service center to have it check however they won’t acknowledge my warranty coverage since I purchased it outside my home country. This implementation is appalling knowing that you are all in one company. I emailed to Apple store in Staten Island, New York yesterday but didn’t get any respond from them and now I made a schedule an appointment at 9am with the support team under this case number 100823713699 and no calls coming from them. Also, I have this case number 100823182513 which is still pending and has thorough details on my concern. This is so frustrating and I hope someone will reach out to me.