A Lapsed Policy?

I just got a letter from my insurance carrier saying my shop insurance had lapsed. The company claims I have not made a payment in two months, but I have canceled checks to prove that I did. They need to fix this problem immediately as it is an error on their part. If I missed two months payment, they should have sent me a letter after the first month. I’m very frustrated at the moment and will definitely find another company to deal with if this is not corrected immediately. We cannot do without this type of insurance on our property.