Were my actions appropriate or did I overreact?

I'm not a very big guy but I'm fit most people wouldn't take me as intimidating but I know self defense I have had intense legit kung fu training and self defense through martial arts. I was at the gas station and someone was asking me for money because they ran out of gas I simply ignored them because I saw the gentlemen in the car ahead of me give them money and I saw a clear twenty handed to them. It was a group of 4 people and they were just asking everyone for money. This made me mad so whenever they called to me for money from their car across from me I acted as if I didn't hear. When they walked up to talk to me I decided to have a little fun and speak back to them in another language. They responded to me like you know english! I continued my babble. They got back in their car and from the window they said sir come here I walked up because I wasn't afraid of them they got out of the car as I approached and as I came near they pulled a Knife I saw it coming and disarmed them they tried to retaliate and I hit him once in the jaw he got in the car and drove off. I didn't get the license plate. Should I have hit them? They could have been just messing around??