How to tell him im not interested?

two days ago this guy asked me to homecoming. I was suprised because this was the first guy to ask me to a dance evr. So i said sure. The next day i thought about and I realized i didn't even know him so I told him that we cant go together because we dont know eachother or have any cles but homeroom together. He said okay. Then after school he asked me for my phone number, and to come to the game with him. I didn't want to give him my phone number so I said sorry but i lost my phone, and i said i wasn't going to the football game. Im not interested in him at all what so ever. I said sorry for breaking our homecoming date but it would be ackward to go with someone I didn't even know. Im scared he still thinks im interested though. How do I convince him Im not interested in a nice way