Touch screen (Digtizer) with area that doesn't respond to touch

After I had a technician replace my cracked iPhone 5S screen with a new one from iFixit, I found that the new one's digitizer/touch panel was non responsive on a thin band a quarter of the way down from the top of the display. I can still use the phone, but the fault can be annoying, specially when I scroll, as it causes the page to jump; if the item is right beneath the "dumb" band, I can't select it.

I contacted Ifixit CS, and I got a reply from a guy called Mike with some steps for cleaning the "connections and contacts" between the display/digitizer assembly and the sys board. Unfortunately he ended his email asking me to send a "a photo of the lines you're getting and we'll go from there" if the fix doesn't work, which means he's assuming this is a problem with the LCD, which it is not. It is a problem with the touch panel/digitizer. The LCD is fine.

I replied explaining this to him, but unfortunately already three days have gone by without a word from him or anybody else at iFixit. I also sent a new message today to iFixtit CS through this website, and unlike the first time they haven't even acknowledged receipt of it. Though Mike's solution sounds reasonable, I don't want to waste money and time on a solution that may not be the correct one.