https://www.apple.com/support/iphone6plus-multitouch/
If you have a iPhone 6 Plus heck out this page.
You can make a Genius Bar appointment and have them replace the phone for the cost of the screen $149 plus tax. If they don’t have the phone in stock because the iPhone 6 Plus is no longer mass produced hey can order it for you which might take a while. Make sure you have an iCloud or iTunes backup of your information because they can not do it for you.
Keep in mind you will be paying to replace this phone with the same exact make and model. Explore upgrade options before deciding.
This sounds like a hardware defect. Start with Contact Apple Support and discuss the issue with them, and see what they recommend. You may need to make an appointment at a Genius Bar to have the phone serviced and possibly the display replaced. The cost will depend on whether or not the device is still under warranty.
I have a problem related to my iPhone
