I rarely go looking for answers, so you better feel special :P I can't guarantee this is it, but its the closest I could find. 415-285-4255 I found that by searching the address of Instagram's office, and then searching that address's phone number, so I'm not even sure it would be right. But I tried!:)
You cannot contact Instagram staff by phone number. Furthermore, the 13 staff that were employed along with the photo sharing program were purchased by Facebook. Consulting Facebook administration can help you find out the best course of action to take. Read more details at http://en.wikipedia.org/wiki/Instagram.