Is it me or is it everyone else?

It seems to me, if you email someone, requesting a quote, a job to be done, asking for information or something that requires a response, then good etiquette states you should reply and acknowledge the email, even if you don’t have an immediate answer.

Over the past year, different people I do business with have not responded to my emails of request for assistance or advice and the end result is I send more email messages and then end up ringing them because I think they are not getting my emails.  Then they think I’m being impatient or a nag!

How do I get across to them that they should actually just hit reply and let me know they’ve seen my email and they’ll get back to me later with the information I’m seeking?  How am I supposed to know they might be researching my answer rather than just ignoring me?

I’ve taken to asking them in my email to please reply and acknowledge they’ve seen my email so I know it hasn’t gone astray.