Seriously, this is a technology company? If they mean to cap at 250GB per month, just halt service during the month when 250GB is hit. Don't let the customer go over, warn, go over, and then suspend them for a year. Seriously, if they are metering it, they can implement a technology solution to halt when the cap is hit that month and not even have this ridiculous abuse of customers having to 'self monitor' the behavior of all the software they have running.
If they want to cap, they need to cap customers with a technical solution.