Chosen Solution

I replaced my iPhone 6 screen about 2 months ago. After about a week, the top portion of the screen was coming unglued. Now, the whole left side of the assembly is out of the frame and I can literally sit here and push it in and it come right back out.

Many third party screens do not have the proper adhesive to hold the screen down. I would take the screen back out and use some thin electronics grade double side adhesive(linked below) to readhere it. Also, leave negative feedback from where you got the screen to prevent others from buying the same dodgy screen. Feel free to buy it somewhere else if you find it cheaper, I just linked the first one I found. https://www.amazon.com/Octopus-Glue-Anti