OVHD no exchange on faulty usb

I received an Ovhd 64g usb as a gift. It is giving problems and I saw that there has been faulty usb reports. The store where it was bought from doesn't want to exchange the usb as I don't have a slip, as it was a gift. And the person who bought it as a gift doesn't have the slip anymore. I made contact with Ovhd and their response is, sorry, no slip, no exchange. I am quite upset about this response as this is obviously one of the faulty usb's that I have. Your service is really not up to standard. You don't even want to exchange something which you admitted is a faulty unit from your side. Totally unacceptable.