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Why not go straight to Bullfrog?Bullfrog Spas Contact Information7017 West 11800 South, Herriman, UT 84096, United States of AmericaCustomer Support: +1 (801) 307-3676Didn't you buy a floor model/demo unit? If so, the dealer is probably responsible for the wrong cover being included. If it's a new order from Bullfrog, I would call them then get with your dealer with their response.
They changed the corner radius to a smaller radius and accidentally gave you the cover for the old larger radius. That's all. Tell your dealer this. They redesigned the spas last year and though they kept the overall sizes the same, they made the radius smaller.