Go buy a car that can get 100 miles a gallon and go 130 mph. Then after buying that expensive car the manufacturer goes and makes all the cars produced from then on only go 30 miles a gallon and can only go 100 mph. Then if he sent out people to go and make your car only go 30 miles and gallon and only go 100mph too wouldn't you be pissed off and be upset when you aren't given a refund?
It's a basic thing in games, never edit already bought items that can't be refunded unless its a game breaking glitch.
Games that do it should expect they will have to do refunds, its their own fault.