Every one experienced with requesting and getting a Money Back Guarantee from a host?
Do you have to explain the reasons you want that?
How does it works? They refill with the wasted $ your credit card?
Well, I can answer your question from the other point of the fence:
Depending on the host, there are different conditions you must meet to qualify the refund. Some hosts will not refund your purchase if you've used a certain amount of resources while others will refund you as long as you haven't violated their ToS.
The best thing to do, is carefully read the ToS/AUP of your prospective host before buying so that you know what you're getting into.
(and yes, usually the money is just credited back to the CC)
I do not see how this question can be answered fairly as it depends. Each and every host should have a terms of service in place and it should explain their policy.
If you do not see a terms page I would suggest looking elsewhere for a host as *most* usually offer some sort of guarantee.