A lot of folks want to call and want to ask me about things - 
Should I buy this machine ?   I have this problem I want to talk to you about -
How do I do this or that - and so on.... 
I am a One Man Shop - I do ALL the work myself.    
I cannot and will not take phone calls once I start doing repairs
on equipment in my shop - and I am VERY busy.
I can't just break concentration and work when in the middle of a repair.
 
Another reason is that with an Email, I can think about it before I answer it
Plus with emails I have some record of the conversations 
  
A guy recently emailed me saying I had not returned his email 
about VU Meters - and was pissed that he couldn't call me
I emailed back saying I HAD responded and had the dates and emails I sent him.
He had just forgotten 
Another guy was pissed he couldn't call me and talk to me,
and was quite rude in his language in a later email.
Telling me I was a jerk because I didn't call him back.
If you have to get rude about that, I can't help you or work for you.
I also get phones calls similar to "This is Bob D over in Okaland. Please give me a call" 
I don't know who this is.... or what the call is about.   It is likely spam.