Why won't my music and apps stay enabled?

I did everything as instructed on my new iphone, eyt the mucis and apps automatic download option does not stay enabled for more than 5 secs. I called tech support and they think it's a software glitch, but have no solution. My iphone is 6 hours old 😟 Back to the store we go. If anyone has an ideas, please share. I have a feeling APPLE is not going to exchange this phone,. I am not a happy camper. It's like buying a new car with a flat tire.