I noticed that also, but in a second reading of it, it does make sense. Perhaps this wasn't the
intended meaning, but ITSPs are paid, and some services ARE "complimentary", including SIP accounts, free DIDs and free incoming lines, and at the moment, GV and Gchat are complimentary.
Again, maybe that's not what the author intended, but even so, the word still works and still makes sense
. Even in the voip context.