What do you think about this ?

Do you think this member deserves a negative feedback ?

I've an add running to sell some speaker cable and this one member emailed me the first day I put the ad saying, I'll but right now if you accept my offer, I accept and emailed back to him and did not get any reply.
I got a new email from him today after 15 days saying , I'll but the cables if you accept this price, I accept and email back to him and I don't get a reply at all.

How do I stop this nonsense ? Should I leave a negative feedback ? Appreciate your opinion.