Decks Unlimited Cincinnati

Decks Unlimited did work on our deck in 2006 involving repair to the support structure as well as resurfacing with composite decking. We recently had our home inspected due to our home sale and the inspector informed us that the manner in which the posts were repaired had created a structural concern and was not an accepted method of repair. I contacted Deck Unlimited and a representative came to the house and agreed that the posts should not have been repaired the way they were. He recommended replacing the posts (5 in total). I then informed him that it was his company that had created the issue back in 2006. He then asked to see the inspector's report which described a suggested repair. After not hearing back for one week I contacted the company again and received an email quoting a repair charge of $120/post ($600 total) to repair the posts per the inspector's recommendations. They created the structural defect and now want to charge me to fix it. They are not standing behind their work nor taking responsibility for their mistake.