Same thing happened to me. My car was insured for $4000 when I purchased the policy and for the year thereafter. I get my renewal notice and it states that the car is now insured for $2900, just like that, without any reason, or authorization from me or anything. And what's more, the premium rose by a dollar! I think my car is worth more than $2900, especially since it is converted to dual fuel and other cars similar to mine are rarely seen under 3500 on the used car market.
But then again, what else is new in life? Rampant price increases without rime or reason and getting ripped off left right and center.
Going to be shopping for insurance elsewhere I think