I've had my twist for about a week now and all of a sudden tonight the button is starting to stick in the on position. I have to press it again to get it to shut off. It doesn't stick every time but more than I'd care to deal with as I now have to actually look at it to make sure it shut off. Is this typical? If not, I bought it at a B&M. Do they typically do exchanges for defective equipment? I know this ain't Target. Lol