Same thing! They called at 9pm, I didn't answer. I called back and it was exactly what you said. I waited for 5 minutes and then it hung up on me. It was saying thanks for using my cell phone and how im "smart" for using my cell? That I could register on my cell to win $50k. It sounds weird/strange. But this happened. They also called me yesterday.... 2 times in 2 days. Hope it does not continue.