Their replenishment policy just sucks. You sign up, choose a plan, get your credit card charged that amount, then have 30 days to use it up. So in essence they first charge you allowing you 30 days to use it up, and keep the remaining balance at the end of that time, even an untouched balance. With so many other services available without that clause, it isn't worth the risk of forgetting or, in my case I was on vacation when the replenish date arrived!