Your request is senseless. You're receiving a discount for the service and expect to be able to suspend and reactivate that service as and when suits you. As far as I'm aware, that business model doesn't exist in the real world without some form of financial penalty.
If I understand the OP's discussion correctly he is not receiving any kind of discount. They have two kinds of payment model - Pay&Go and Unlimited ($50/month).
They're calling the unlimited model a "discount" since presumably if you send enough it is cheaper. So it isn't unfair to call it cheaper, but it is kind of silly to suggest he should eat a fee because of the "discount" he may or may not be benefiting from.
In general that business model is extremely common in the real world. My current phone, Netflix digital, and broadband subscriptions are all "unlimited" and I can cancel for free whenever I want (except in the first 12 months with broadband).
I think you're confusing a "unlimited fixed fee" service with a "12 month commitment at a reduced fixed fee" service. Not the same thing and this case appears to be a month by month rolling fee, not a discounted longer duration.
Would Netflix allow you to cancel right now and return in two months with all your preferences and viewing history intact?
Yes. And my phone company would let me keep the same number if I did that.