Refund is only available when the goal rank is not achieved at the end of the package. (Please note that the rank should be the time-period average rank, such as a one-month average or three-month average). In any case, the value corresponding to the ranking achieved during this period will always be deducted from the total received.
I have been a devoted customer at RankStore.com for the past 4 years and they have been one of the few companies that have stuck around despite the many changes to the Alexa algorithms over the years. As best as I can evoke, I have used their services for 28 websites over the years. Some were client websites and others were personal ones. But the results have been outstanding. These are the guys to go to whenever you need a quick boost to your Alexa ratings.