Hello, thanks for your question and patience. From what you described at some point when the previous owner sent it in for repair the parts where reused and the serial number was already used. Hence why it is refurbed. The serial should have been rectified with a new number it was reissued from Garmin. Anyway, to solve this problem you will need to contact Garmin directly. Here is the customer support information.
If you tell them I purchased a refurbed Nuvi 255W and when I try to register it says it is registered to another user but I have never registered it before, they should be able to help you register it. If they cannot get it to work they should send you a new device. Garmin usually has good customer support.
For your transactions with your card I would be sure that they did not go through. If you can check your account you should be able to see the pending charges and cancel them if you contact the company. You can also bring this up when you talk to Garmin.
Anyway, sorry you could not register it today. If this was helpful please hit "Accept."
If you have any other questions please let me know. Thanks again.