CNA National Warranty (MAXCARE/ Carmax Warranty) Customer Experience vs. Policy Scottsdale Arizona!!. Horrible customer experience with this company. They put policy before customer experience. Be careful purchasing a warranty from Carmax for CNA/Maxcare. My car has experienced ongoing issues with engine coils. I have a total of 6 engine coils that have been going out one by one since June 2017. My car has broken down 4 times so far. My dealership has recommended to CNA to fix all of them or my car will continue to break down. At this rate, I can look forward to being on the side of the road 2 more times. This is an awful experience and it’s clear that no one has done a cost benefit analysis to help them understand that they’re throwing away money in labor, towing, and potential purchases of their warranty products through Carmax. Unfortunately, I will no longer do business with Carmax because of their affiliation with this company. Do not purchase anything from this company if customer experience matters to you.