Why is it so hard to buy parts from people

I need a phone call. Period. I've already been on a couple goose chases from emails, whatever, only to "get there" and no place, wrong place, or nobody home. AND I GO ARMED

Yesterday when I scored the HVAC manifold/ gauges I thought "it was gonna be another one." Sent an message, as usual, explaining "this is my laptop, my phone is not smart, please VOICE call" No response. 4 hours later, I went "hello, anybody" and I get "yes I still have it." Well that is not what I ASKED you. So I told him to call, and he turned out to be a nice guy. I've no idea WTF the problem is "at that end."