Looks like there may have been financial trouble brewing since March:
http://biz.yahoo.com/pz/070313/115433.html
(see "Financial Restructuring" where they admit they were in default on a loan).
Doesn't anybody (sunrocket, voicestick, callkey, and especially their investors) realise that a business plan should have a way of making profit built into it from the start. Don't just go out giving away services or selling them cheap, in a business where the revenue per customer is tiny, and then hope to find a way to make money later from volume. It's daft.