I am a permanent resident of US. My mother visited me last year on a 1
year multi-entry tourist visa for 2 months. She reapplied this year
and she was told that the visa would have been issued, but it appears
that someone else has used the same expired visa number that she has.
So, additional processing would be required. Consular officer said
that it would take 3-4 weeks. It has been 3 months and we still have
not heard anything. I know the additional processing is done by the
department of state. They have a phone number to call, but all they
can say there is whether the case is pending or not. Every time I call
it's still pending. The DOS visa service center says that processing
times are indefinite. My mother has been a teacher all her life and is
63 years old. Is there a way to speed up the process?

Dear Visa_question,

I hope the site of the US Citizenship and Immigration Service can
provide some help:

http://uscis.gov/graphics/index.htm

I must admit, that there is probably nothing that directly addresses
your unusual problem, but maybe you can put your questions to someone
other than those you have been talking to.  Bureaucrats around the
world hate to back down from something they have said before, much
less to admit a mistake or that they are not the final source of
information.

As you have probably already recognized, the story that the same visa
number (now expired) has nothing to do with anything your mother did.
The visa was stamped or pasted in her passport, and presumably she can
prove that it is still there.  If the same visa number was - or seemed
to have been -  issued to another person, or was incorrectly recorded
within the USCIS or when that person entered the country, that is
would be an error that should not have an influence  on your mother's
situation.

I offer that as a little help for possible further discussions,
hopefully with someone willing to listen.

Spend some time with the site.  Maybe it will suggest other
approaches.  At least, you will be better informed and prepared for a
discussion.
The site warns against lawyers who claim expertise on immigration
problems, and another questioner mentioned that she got conflicting
advise.

And my comments are, of course, no professional or legal advice as the
disclaimer at the bottom of this page emphasises.

Good luck!

Dear myoarin,

Thank you for your comment. Yes this is a strange situation, but
apparently there are many people suffering from the procedure and
indefinite processing times. How can that be that there is no limit on
the time it takes to process an application? This is definitely
frustrating.

I suggest that you ask your Senator and/or Congressman to help. This
worked for me a couple of years ago.

What would be the best way to contact senator or congressman? Is that
regular mail, email, phone call or physical visit to the office?

Dear Visa_question,

Czh-ga has a very good suggestion, even if you are not a US citizen. 
Let them assume that you are.

I would suggest that after you have gained as much info as you can
from the USCIS site, that you call the person(s) you have already
spoken to, to get their most recent comments; then speak to someone
else  - if the site provides an alternative, noting the response you
get.

If this is still all of no immediate help, then I would write separate
identical letters to "your" two senators and "your" congressional
representative, outlining the situation and past responses, detailing
the most recent responses.
And ask them to confirm receipt of your letters and what they will do.

Here are site where you can find them:

http://www.house.gov/writerep/
http://www.senate.gov/general/contact_information/senators_cfm.cfm

If the Congress and Senate are in session, write them in Washington.

Don't be too humble in your letters; you have been getting a
run-around,and "your" representatives are responsible for good and
fair governance.

Good luck!