A:AnswerI had this problem too. It's actually not a problem. You have to "unselect" comfort mode and then the + and - will work. Again, you can't have any buttons selected, just turn it on and then use the + and - button before hitting any other button. Took me a while to figure this out as I did the same you did it sounds like.
A:AnswerI had the same experience. I could only use it for a few months before the compressor stopped Thai summer :-(. It was a piece of junk that I bought :-(
A:Answergo to bestbuy.com and check Insignia™ - 10' 3-Outlet Extension Power Cord with model number NS-HW308.
Rudson S.| Insignia Support. https://www.insigniaproducts.com/contact-us