OH USA - Auto incident, car untouched, no police report, person's insurance is calling

My husband was in a sort-of fender bender involving 3 cars. Apparently there was a long line of cars and it forced everyone to stop quickly. The lady in front of my husband hit the car in front of her. My husband's car did not hit anything, but for some reason he decided to get out with everyone else. The lady said she hit the guy in front of her because she thought my husband was going to hit her. No police were called thus no report was filed, and again, for some unknown reason my husband gave them his phone number. Now this dude's insurance is calling my husband. Are we obligated to respond? Or can we ignore?