I agree with the pitboss
I'd like to see you try and convince any pit boss of your argument when a match play coupon is involved. I've tried it countless times and always lose the argument as well as the coupon. The excuse is always the same; "you lost the base bet and insurance is a separate wager and you can't insure a coupon." My argument is that if you can stick it in the betting circle, then it's insurable. Stupid pit critters anyway.
Unless you also have a bj, you lose the original bet if the dealer has a bj. Insurance is simply a sidebet available when the dealer is showing an A. I have played in places where one can make an "insurance" bet up to the amount of the original bet (instead of just the more normal 1/2).