I use Amazon a lot so pay for prime - but was aware of this for quite a while.
However about 7 years back I switched insurance companies for my car and despite informing (by phone, email and mail) my previously insurers I would NOT be taking up the "generous" inflated quote my account was debited by them.
So in essence I had two car insurances at the same time and took a while to get canceled / refunded. In their small print the also a clause about contacting the police if they suspected you were driving without insurance...so
Thats the main reason why I pay mine in one lump manually. It gives "them" a strong incentive to contact me, and prevents any nonsense about automatic entitlement to my money.
Up to a couple of years ago I was shopping around, winding up with quotes that were much of a muchness, then I contacted a non-comparison one. Over £100 per year less, same cover, painless transfer. The last couple of years their quotes have reduced, the competitions' have increased. Not the lady dressed as a pirate, but the gangster enforcer character. As ever, I'm hoping that I never find out whether they are any good at handling claims, but that is true whatever company you place your bet with.