Using a needle/pin works well. I did what another person mentioned in Step 8. Pry up from the back corner with the tip of the needle. Be gentle. One side will pop up a tiny bit. Move to the other side and gently pry there. Mine popped out completely at that point.
Did you have any luck with this? I had the same exact problem. Also the phone is dropping calls and not connecting calls all the time. I struggled getting the antenna connected but finally it snapped in firmly and I thought it was good to go.