My Court Orders Aren't Good Enough

Update: So, the DA talked to the lady, and told her that I was telling her the truth--that she was under court order to be here and to produce the records. So now, she's turning them over. I guess I figured this is how it would end up all along, which is fine. I think I just got seduced by the feeling of power--that with the stroke of a pen, I could have someone arrested. This must be what prosecutors deal with every day.
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Original post:

My client is charged with shoplifting from a department store. I subpoenaed the custodian of records for the store's loss prevention office for any records they had related to the incident. The case was set Monday. The woman didn't bother to show up. I thought it might have been a mistake or oversight on her part, and my case was being held behind an older case, so I tried calling her. She informed me, in essence, that she is working with the District Attorney (who she at one point described as "the attorney we pay to handle these things for us"), and she does not have to obey my subpoena. We'll see how she feels about that when the sheriff's deputies show up with a writ of attachment.