I bought coverage from Nationwide Automotive Protection.
Called within 30 days to cancel, had to leave a message. No one called back though I did get one call asking how things were a few days before my cancel call/message.
Got a call from that 800-416-3800 number today and let it go to vmail.
The message said call Linda with NAP at 8003765553x264.
When I originally made the deal with a guy named Shane, he was super nice and worked with me to get a payment I could deal with for the services promised.
When I called Linda, they transferred me to Shane who had become a hardass saying I'd not made my second payment. I told him of the cancel call due to an error in mileage on the paperwork they sent me and that unless they'd wave the 1000 mile - 30 day waiting period, I was still cancelling. I even offered to pay the entire 1st year up front. They refused so I cancelled.
I do not believe them to be reputable, but have no other experience with them.
I did use a service like this once before and it worked out well for me, but that was over 10 years ago.

Nationwide Automotive Protection. Had the television add to call for a free rate quote for what they called, "extended auto coverage".  Instead they tried to force me to purchase insurance when it was impossible to afford the monthly payment. Just a return call.

Called asking for someone else's name. I've had my phone # for 15 years and nobody by that name lives hers now or in the last 15 years. He told me that this was the correct number as of last year. Then he sarcasticly said, have a nice life, I then told him the same and hung up.