Front Seat Head Restraint problems of the 2008 Toyota Highlander

At 5:00 pm on may 16, 2017 I drove home from work (15 minutes of in-town driving) everything was fine. I parked in the garage and went inside to prepare to leave with my family for my son's senior honors night. At 5;45 pm we got into the car and immediately my mom and my husband said, "what's burning?". It smelled like paper burning. Before leaving the house, my husband popped the hood to make sure there wasn't a wire or something else burning under the hood of the car. We dove 10 minutes to town to eat. We stayed in restaurant 30 minutes. When we returned to my car, my mother got in the passenger's front seat and and my husband in back and we all smelled a strong smell of something burning. I looked at my mom before starting the car and saw the black, burnt headrest. It appears there was an actual flame at some point. Everyone got out of the car, we removed the headrest, but the back left side of the passengers seat was still very hot to the touch. My husband drove the vehicle to the fire station nearby, since the Toyota dealer was already closed. The firefighters unplugged the wires from the seat. The seat cooled back down.