the bracket holding the rear quad panel on the right hand side of car keeps coming off. How do I fix this to prevent that piece from popping out and not lining up with a straight seam

What is your question?

Car was rear ended and only damage to repair was new bumper and lower right hand side panel, but that panel keeps popping out and leaves a gap where two pieces are supposed to line up. The bracket holding the rear quad panel on the right hand side of car keeps coming off. How do I fix this to prevent that piece from popping out and not lining up with a straight seam