In my opinion, I think for the buyers who dont reply your messages after you going through their messages, i think you should improve on your commuication skills, your marketing startegies. Probably the buyers were not impressed with your replies. And you knowmyou must present yourself as a professioal to the buyers ad your replies must be a soulution finder or problem solving and must always end with a question... I think that will make the chats with your buyers iteractive and conviction..
I hope i made a point?