iPhone 6 Plus Multi-Touch Repair Program
You might not know this, but Apple's got a Multi-Touch repair program going for iPhone 6s Plus users.
Apple's "determined that some iPhone 6 Plus devices may exhibit display flickering or Multi-Touch issues after being dropped multiple times on a hard surface and then incurring further stress on the device."
If you start noticing these issues on your device, your device is in "working order," and you don't have a cracked or broken display, Apple will repair for your phone for $150.
Apple's been contacting people who have paid for a service repair related to this issue, but if you haven't heard from Apple yet and paid for a repair, you'll want to contact Apple.
For more information, please reference Apple's website.