Venhin has already explained that there is a confirmation box before you purchase so they can't refund any items you've already purchased.

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it is almost impossible that this situation will happen.

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there is a possibility that you may tapped the buy button and instead of no, you tapped the yes and you've purchase it, and you didn't realized because you thought you closed the description only after the event and realized that your money was taken/paid to something and
it was pbp.