Discovery, worst insurance coverage in market

Never insure with Discovery insure. They do not disclose terms and conditions and exclusions and only find an issue once it comes time to pay. We had a specified engagement ring that was covered with Discovery. This was ****** and my wife was heartbroken. Upon claiming they advised the needed the valuation certificate. This certificate was ****** with the ring but I was able to send them the certificate for the diamond, confirmation of receipt of the valuation certificate from the previous insurer and confirmation that the certificate was sent to them when the ring was initially insured with Discovery. This is insufficient for them and they do not want to cover the insured value. Their default position is not to pay. I left my previous broker to join Discovery and when I contacted her to try see if she had a copy of the certificate, she advised half of her day is spent trying to get Discovery to pay claims. She advised they are the worst insurer when it comes to payments and I have to agree.