phone etiquette

Apparently neither of my parents understand that there are some situations when I cannot come to the phone (and when those end, become situations when I can, I will call back). My phone rang-- I'm not trying to give the impression that all I ever do is volunteer, but the dinner crew at a shelter I volunteer with canceled and a call went out for last-minute dinner preparers-- anyway, my phone rang just as I was serving dinner. I didn't answer. Fifteen minutes later, it rang again. By then there was a lull (but not enough of one that I would have returned the call then and there rather than waiting until I'd left).

A.: Hello?
Dad: Hi. This is actually the second time I'm calling.
A.: I know. I heard the phone ring, but I couldn't answer it. It still isn't a great time for me to talk.

***
This is not the first or second or third time something like this has happened. My favorite was when my parents called one Friday night, I got the message at 2am, and then was woken up at 7:30 in the morning by angry parents asking why I hadn't returned their call. No concept of I may not have gotten the message or didn't have time to return it. I will return it when I have time. Even when I was calling stoner HR guy-- i.e. when a job depended on it-- I gave him more time to return calls. I didn't call him at 6pm one night and then again at 7am the next morning asking him why he hadn't returned my call. Now that I think about it, my mom's claim that I didn't call after dad's operation-- even though I'd called three times that day at times when we thought he would alread be home-- could have been a reflection of the fact that she left me a message after I'd already gone to bed, and called me again in the morning before I had time to return her call.

Am I overreacting? Do any of you do this, i.e. not trust the fact that someone isn't answering or returning your call because it's not a good time for them to do so, and so calling soon afterward? Is that logical?

***

Dad: Have you done anything about your visa yet?
A.: Yes, I submitted the application for it.
Dad: Oh, okay.

Mom had scolded me earlier, because that's what she does, for dilly-dallying such that the Chinese government raised its fee. It's not like that was in any way predictable, like after a certain date the fee would go up, so I hardly saw the reproach as deserved.

My parents apparently equated my decision to deal with the visa once I worked in the city (or had a few days off) with my failure to deal with the visa at all. Had I thought faster, I would have pointed out to dad that I managed to visit five countries last year, two of them with additional entry documents required, without adult supervision.

This isn't a matter of hurt feelings-- that my parents seem to believe that I wouldn't get anything done without their reminding me is not what worries me (in fact, I think it's kind of funny). It's that historically, their perception of my incompetence has motivated them to get involved... to interfere, micromanage, etc.-- and as that involvement has only complicated matter, it's in my interest to discourage it.