Yep, what everyone else has said. And if you're reading on Kasamba, the people who do that are hoping you're going to refund their money because you're not a "real reader". Don't worry about it and don't refund.
Besides, you're not always going to be right on with your readings and even when you're right one, you're not going to please the sitter. Pleasing the sitter isn't your job. Your job is to read what the cards have to say. Contrary to what's commonly believed, making people happy isn' what your goal should be. Your goal should be to read what the cards are saying to your sitter, good bad or indifferent. They don't have to like it, they don't have to rave about your "accuracy"---you just have to strive to get the message right and convey it honestly, tactfully and compassionately----or not. Because sometimes you shouldn't convey the message and you also have to know when you shouldn't deliver it. Not because you're too chicken to deliver it or because you don't want them to get upset and say you're wrong because it will hurt your feelings, but when not to give it for the sitter's sake.
HOWEVER, on those places like Kasamba and Keen, they DO want you to please the sitter by telling them what they want to hear because that's how they make their money---from repeat happy customers. So reading for them is going to compromise your ethics if you're to do well there.
You can't be in it for your "accuracy" and the praise you get. Not that you are, but you know what I mean. You have to be doing it as a service to others. Kasamba isn't the best place to provide your service to others.