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Company asking for card details to refund over email
If it is a well known company that wants to give you a refund, I would not worry about giving them your credit card number.  However, I would never type my credit card number into an e-mail message. E-mail messages are very insecure, and can be read by many people along its way to the destination. They also can be archived in many places, meaning that your number will continue to be posted out there for someone to grab in the future.  If you need to give this company your credit card number, do it over the phone.  Having said that, ultimately you are not generally responsible for fraudulent charges if your card number is stolen and misused. I've had so many fraudulent charges, despite my being relatively careful with my number, that I don't really worry much anymore about losing my number. I just check my statement for false charges, and when they happen,  the bank cancels the charge and issues me a new number. It has happened to either my wife or I maybe 5 times over the last two years.