Selling parts and lack of manners.

Ok, so here's the problem I keep having as a seller! I list a part, I get a message right away cause I must be selling at a good price, I message the first guy in line and mark him as the buyer and ask for his zip! Boom, 3 other people say ill take it too before I can even get to the thread to post a sale pending on the item post! I post sale pending in the thread but maybe not everybody reads that, so people who messaged saying ill take it may not know that! Next thing you know, there are 7 people (true) who want the part while I was posting a sale pending in the thread!

Do I have to message everybody personally to alert them of their place in line? From my phone? And then go through the 300 messages I have in my message folder and delete the 6 from this sale, the 3 from the previous 27 sales, all from my phone?

And because everybody is following the rules much better now, no one is posting a "PM Sent" to mark their place in line on the thread, so other than my post, which may or not be read , there appears to be no interest at all in the item!!

Happening just about every listing now, and I'm only listing a couple items at a time!! What should I do the make the masses happy?......

don't really have an iron in this fire but I do see this pretty frequent, not just in sale ads. seems like many folks don't bother to read any of the previous posts.