What do you think about this situation pertaining to a $500 OFF coupon?

I had an estimate done to install 800 square feet of paving stones in our yard around our house from a local paving stone company. The estimate was nearly $10,000. It sounded good enough especially since I had a coupon from that company for ”$500 off on any project greater than 200 square feet”. But when I showed the coupon to the woman who did the estimate she said, “Oh, I have already taken the $500 off the estimate”. But on the agreement/estimate that was presented to me, there was no indication of the $500 deduction.

This really bugs my wife as she loves to use coupons. But I’m very willing to just let it go. It is a good deal with or without the coupon especially with the great quality of workmanship. And the estimate is the lowest that I’ve found.

What do you think?