That is one thing that I don't like about the cryptocurrency and the blockchain technology. Transactions cannot be reversed. The only chance that you will be able to get back what you have sent wrongly is when you were able to send it to a proper address and the person on the other end of the line is kind enough to return to the sending address what is not his. But of course this is going to happen with only a 2% probability. So let us just be very careful in our transactions. Other things that I don't like are the typical transaction fee and the long confirmation time.