See my answer to your duplicate question. With these details, it's apparent that you ignored not only a demand letter, but a court-issued summons. That's where you made a big mistake. You will need to file a motion to vacate the judgment and see if that works. That will probably require you to hire an attorney.
Whether the store's people came to criminal court or not makes no difference on whether they can sue you. A lot of people make that assumption, but it's not true. You need to get to a lawyer now, and I do mean right now.
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I just finished answering a similar question. My response was, and is, that a civil demand letter does not create an obligation to pay. but to pay special attention to any communication from a court. Being sued is not the same as getting a letter from a law firm.
The above is general legal and business analysis. It is not "legal advise" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.