Where has my music gone on my iPhone?

I just got an iPhone 5s and have been listening to my iTunes music on it at home. Now I went to listen to a song, and only 20 songs are there (out of 2,000 that were there). The strange this is, as soon as I turn on the Wi-Fi and get connected, all my songs are there.
So with Wi-Fi on, my music is there. With Wi-Fi off, most of my music is gone. How can I fix this so I can listen to my music on the go?

IPhone not recognizing new location?

I recently moved from one city to another. I haven't changed my phone number to the new area code (720 to a 719). Everytime I look something up on Google, or ask Siri a question, It gives me results in 720, but not 719. It is annoying to try finding new places to eat or shop when I'm only getting 720 results.
Any way to teach my iPhone i'm now in 719? My location settings are all on as well.

Pink wet stains in iPhone 5 screen?

I was at a foam and glow party and now my phone screen has wet stains but they're pink. Anyone I can get rid of them by like putting it in rice or something? Phone works fine and nothing's wrong with it

IPhone 5S Covered in Apple Warranty?

I have an iPhone 5s and overtime I have used it without a case, the sides and particularly the top of the housing has been roughly kept with dents and a number of scratches. The back of the phone has a thin scratch which isn't noticible, but the main problem is the switch and sleep wake button keep sticking forcing me to use the accessibility settings to operate them. This is very annoying, would apple replace this as I'm still in my one year warranty and haven't actually used it once yet. I'm asking here first as the nearest apple store is around two hours away! This is all mainly due to the kids using my phone and a very busy work! Much Appreciated (images attached) - JoshIPhone 5S Covered in Apple Warranty