OK, you want to put caps on usage, and want to be like every other utility with metered usage, fine. You better work like one then. If you sell me a 10Mb line it better be 10Mbit. I don't pay my electric utility for the quoted electricity 'sometimes' and I will not pay for metered service that doesn't work as advertised.
If it doesn't work as described 24/7 I would call them 24/7 until it does.