Classic Car Insurance Hagerty vs Grundy

I have Hagerty. I stopped using Grundy after they couldn’t figure out how to remove a Mustang off of my policy even though I sent them a notification when I sold it. This was two years after I sold the car plus i didn’t list it in any of my renewals. Long story short they had to issue me a new policy and then the state came after me claiming I was driving my cars without insurance. FYI, it took me a year from start to finish to get the Mustang removed from Grundy’s system and that was 3 years from when they were officially notified that I no longer owned that car. And Grundy is owned by Philadelphia Insurance.