Downgraded - no pro-rate or continue until end of billing period?

I got the email that after Sept 1, my plan would go up by $2.  Having read how difficult it can be to downgrade, I called today to say I wanted to drop to the self-monitoring plan next cycle.  Amazingly, it was done instantly, although I haven't received the email I was told I'd get.  

Anyway, I notice that I was instantly down-graded, but, is there no pro-rating for the rest of the month?  Any other service (phone, streaming, internet) I've ever had, if you downgrade or cancel, you either keep the service through the end of that billing period, or you're cancelled/down-graded but receive a pro-rated amount back. My bill was paid on the 14th.