Sink won't drain. Plumber says the pipes are backwards/upside down. As far as I can tell the problem is that the white elbow on the left is lower than the hole in
CFFE0012-NL - Everflow CFFE0012-NL - 1/2" C X F Cast Brass 90° Flanged Sink Elbow (Lead Free)
Removing L-shaped elbow underneath a kitchen sink - Home Improvement Stack Exchange
Streamline Flanged Sink Elbow,90 Deg,Copper,1/2",C A 03706NL - Walmart.com
Keeney 1-1/2-in Plastic Disposal Elbow in the Under Sink Plumbing department at Lowes.com