Exact same situation and I too believe I know the
individual at the DS you are referring to. Based
on your description of your experiences and what
you've done as a customer, I'd say this DS just
does not understand how to maintain good relations
with customers. Sure English is not their first
language and conversely Japanese is not ours
(typically), so with that should go some give and
take. However, to answer your questions...

1- Should the customer be punished for a deputy's 
lack of comprehension of the english language? 

No. But I think the problem also involves a lack
of understanding about how customer service is
valued in the U.S. and that reasonable efforts are
made to work with them to ensure a pleasant
experience.

2- Does anyone else see a need for more english-
fluent deputies with fair prices?

Absolutely. The two I recommend currently are
Rinkya and AnimeChaos DS. Rinkya is good but can
be pricey. AC is good too, but once they had
technical difficulties that resulted in users
being unable to bid. And in my case the tech prob
was not fixed in time, so I asked them to bid for
me. They couldn't do it b/c they did not read the
email -carefully-, completely missed the
username... so they never placed a bid. I ended up
losing the auction which went really low. *smacks
forehead* Overall I would look forward to seeing
another DS pop-up and give these two more
competition and force them to lower their prices.
More competition for them is better for us.

Lastly, I'd really suggest you post the name(s) of
the DS you used AND the rude people there, so we
can know who to avoid. There is no excuse for
their behavior, completely unprofessional.