My Sunday column arose from several calls I had received from frustrated customers of T-Mobile, whose calls back home to Togo and elsewhere in Africa, Asia and Europe over Wi-Fi network had been free for months, until the company started billing them at up to $1.99 per minute. It's a tale of our times, as VOIP becomes a household word and technologies such as Skype and magicJack have upended the world of telephony. For these customers, however, giant phone bills were an unwelcome blast from the past.