$700 is not bad at all, surprisingly low to me, just think how big that rear center bumper is. In your case, you don't need to replace that huge piece or no replacement at all. Mine was very slightly bend, you couldn't see it unless you know it is there. But the car my Hummer backed into had $5,000 bill to rebuild the entire trunk and rear end. My fault my insurance paid.
Just got the new insurance premium notice, jumped from $800 to $1200 for 6 months of $1/2 million coverage.