Welcome to Justanswer.com, my name is Dustin.I'm sorry to hear about the issue you are having, I will do my best to help you resolve it.
Do you know the model number of your Nuvi by chance, or roughly how old it is?
Such as a year or two, or 3+ years old?
Hi, Im not in a position to call you at the moment, I turned my phone in for a warranty replacement earlier this morning before started work.
However, if you would prefer I can connect to your computer from here, and then speak to you in live chat, have you connect the Garmin and then I can get it updated and running correctly for you personally, on screen.. If you'd like to try that, I will send that of fer to you now.
The fastest way to reverse the payment would be to use the refund link below, and you can auto process a payment yourself.
Disputing the charge through Visa would tie your money up for weeks, if not longer. If it was my money, I would try the refund link below as that will immediately send the money back to visa and then its the normal 2-4 days processing time that visa requires.
If you change your mind and actually want help with this issue, you know where to find me.