I recently ported my telephone number from Verizon Wireless to another provider within the billing cycle, yet was charged for service by Verizon Wireless for the full cycle ... in this case, 19 days of service that they did not provide (my new provider did).
In response to an FCC complaint on the matter, Verizon Wireless stated that their terms and conditions allow them to do this. The amount of money was not much, but when multiplied by the number of customers who leave their service every year, it no doubt provides VZW with tens, if not hundreds, of millions of dollars in revenue for services that they did not even provide.
Caveat emptor when dealing with a company that would engage in such a shady and despicable practice. And if you are porting your number away from them, do it at the end of your billing cycle, so they are not getting away with gouging you for service provided by your new company.
Monetary Loss: $29.