Mid/rear Seats Assembly problems of the 2015 Lexus GX460

My car was parked in the driveway of my home when my friend opened it to get inside and noticed a horrid smell!!. . When she went to investigate, she found the back seat was melted like a tar pit!! the back seat of my car has rear seat heaters and the entire seat above where those were were black sticky goo. 1. The car was parked and off when this occurred 2. There was a bag of dog food on the seat that was unscathed. 3. Lexus is refusing to cover the damage. 4. The backseat is normally where my children sit!!. . . 5. This is a brand new car with 5000 miles on it, and it wasn't even running!! Lexus dealer said they can't open a claim, only me, so I did, they sent an inspector, and denied the claim. . I tried to appeal and they denied the claim again. . Saying they sent me a letter stating why but won't tell me over the phone or let me speak to a claims manager. The letter is being sent my regular mail, so good luck with that one. When I requested for her to email me the response she also refused.