This is probably the hardest and most elusive part of the whole process of getting into the music industry. Unless you already know someone it is pretty difficult to get anywhere past the receptionist and it can be pretty frustrating. I didn't know anyone either and I'm from a small town where most people didn't understand the idea of working in the music business. It may be difficult, but it isn't impossible.
Get Experience Where You Can
There's always a problem getting into any industry: you need experience to get the job but need a job to get the experience. Surprisingly, that part is actually a bit easier in the music world. Ever moderately sized town has some sort of music or performing arts venue, regional concert, local radio station, local band, or something somehow related to music. Find one and volunteer to help in some way: hang posters, carry gear, sweep the stag, whatever. Almost everyone appreciates a helping hand and you've got nothing to lose. It will help you get some connections, something to put on your resume, and may lead to bigger and better things.
Yep, you've probably heard it a million times, but it really is that important. This business is about who you know. So you don't know anyone? Go to local venues and talk to the sound people, the person selling tickets, etc. or find a local music event or conference to attend.
Don't Write Off That Receptionist
So you call Sony and get nowhere. Well, keep in mind, that receptionist isn't just some person answering the phone. He or she is most likely your gatekeeper to the rest of the company, plus in a few years may be an executive.
Be Persistent But Not Pushy
The key is to continue to follow up. It is incredibly easy to ignore someone when they contact you once, but it isn't as easy when they've called a few times. However, do not be annoying or too demanding or call every few days...or even every week. Be reasonable. You want to stay relevant, not get your number blocked.
Thanks for Kenny for the inspiration on this one!