Tail Light Switch problems of the 2012 GMC Terrain

My 2012 Terrain is getting water in the rear left tail light. I was told that it was a vented tail light and the vent was blocked by dirt and debris and they would have to replace the taillight and replace both seals. When I lift the hatchback up water drains out from the interior side of the hatch back into the vehicle. GMC of watertown connecticut says that this is not covered under my extended warranty. I called GMC corporation and they said that this was a defect but is normal with these vehicles. GMC case number 8�3054294483. I have the better business bureau auto line investigating the problem and that case number is pgm1719802. GMC told me the water in the tail light can short out my electrical systems and this defect has been by known GMC from 2011. Since I purchased this car new in 2013 I have had multiple problems such as having the back camera replaced twice, front navigation screen going black, stabilizer malfunction which was also a problem with this vehicle when it came off the assembly line, having the computer updated every year because they say of all the computer chip modules that are installed in this vehicle, just to name a few which are all documented with GMC. I am submitting this to make the federal government aware that this defect is potentially a hazard to the electrical system and has been known to GMC for a long time and they have not corrected the situation. Their solution is replacing the tail light at a cost of $254 without tax. I believe this is a serious defect and if you require more information I will comply to any requests that you have. Also all conversations with GMC corporation and bbb auto line were recorded if needed. Thank you for your time.