Dog Park Injury

The question is how and should I sue my dog park. I've called the city three times about a metal poop bag stand and trash can its an all in one nightmare right by where the small and large fence are located. The dividing fence of the two sides has this metal post with large metal bolts on its back which faces the fence. On our first trip there it caught my dogs eye when he would run up/down the fence with other dogs to chase the dogs on the opposing side of the fence. Later he hit his hip which cut him to the bone another vet visit. After the 2nd call they shaved the bolts off leaving rough and in some areas sharp edges. My dog hit his shoulder on it this week and the laceration was so bad he had to get stitches again for a huge gaping wound with a cone. He'll need a check up. This cost me almost 2 grand. I've complained again to which they apologized and agreed to remove the poop bag/trash bag stands like I originally suggested. Can and should I sue them? Yes my dogs have all the shots of corse. I've probably called them more times about this but at least 3x. Unrelated but this December their gate was apparently broken leading to both of my dogs and someone else's dogs getting lose in the street (parks by main road). They fixed it in late January after my third call. They're not timely and this park isn't well maintained.