Missing piece from Logic Board Step 29 - does it matter

In Step 29 of the iPhone 5C Logic board replacement, it states "Pull the logic board away from the rear-facing camera just enough to expose the gold contact cap under the top end of the board." "Remove the gold-colored contact cap from the threaded post in the rear case, and set it aside."

My phone does not have this "contact" cap piece and there is a gap between the screw hole of the logic board and the threaded post beneath it. I'm trying to decide if spending the $70 on a new screen/digitizer set is worth it since this piece that is missing might be causing completely different problems.

Can someone please explain the purpose of this piece and whether or not the phone can operate normally without it.

Before the screen was cracked and replaced last month, the phone "seemed" to have been working just fine for the past year. I replaced the screen/digitizer with a cheaper off-brand from Amazon and there are vertical lines (pinkish/blue) all over the screen and the left side of the screen does not respond to touch. I cannot enter my lock code to do anything with my phone/data or even back it up. I need the screen to work. I believe the screen is a faulty part since it is installed perfectly and I have attempted all troubleshooting ideas to remove the vertical lines and dead screen.

I know I can buy a higher quality screen from iFixit and get the screen to respond to touch, but last night I decided to re-seat the logic board too and make sure all connections were lined up properly. That's when I noticed this missing part and wondered if there are other problems caused by that, making the phone not worth fixing. Please help. Thank you!