trunk opens

Please help. I have two KEY FOBS. One of them works fine (however, I lost it this weekend) The second key fob pops my trunk every time I hit "lock" or "unlock" on my keyfob. Basically, any button I press, my trunk pops open. IF, i avoid using the remote on the keyfob and use the actual key...

The trunk on my 2011 Buick Lacrosse opens by itself. If I lock the car, it doesn't, but if I leave it unlocked in my driveway it sometimes does. This has caused my battery to die and have to be replaced and the inside of my trunk has gotten wet due to the weather. I am very unhappy and have...