If you search around on avvo, you'll see that the overwhelming consensus is to just ignore the civil demand letters. If you pay, it just means they won't file a smal claims case against you. Guess what? I have NEVER heard of them actually suing anyone for ignoring their letters. Why? Because lawyers cannot be involved in small claims and it's just not worth their time to pursue it. I assume they got the stuff back, so they really aren't out anything. If the police were not called that day, the odds are overwhelming that they will never be, even if you ignore the civil demand letter.
Stay out of that store - they probably has you sign a no trespass warning.
The above answer is for general information only and is based on the information you posted. Every case is fact dependent, so to get a thorough analysis of your situation, you will need to consult face to face with an attorney licensed to practice in the jurisdiction where the incident took place. Do not conclusively rely on any information posted online when deciding what to do about your case.
As Mr. Dane as indicated, the consensus among Avvo attorneys is to ignore these letters. You will get letters sent to your house. Keep out of store. You were lucky you were not arrested.
Andrew Roberts (818) 597-0633/ (805) 496-7777
Wait on this. Ignore the five day deadline. See if you are charged with petty theft (Penal Code section 484(a)). If you are, then speak to an attorney about paying the demand with a notation on the check that says "Paid pursuant to Penal Code sections 1377 and 1378." Include a cover letter enclosing the check, stating that payment is made pursuant to such code sections and if Macy's does not accept such conditions, to return the check. They'll cash the check. Then get the cashed check from your bank and file a Motion for Civil Compromise to have the case dismissed. Hire an attorney to prepare, serve, file and appear to argue the motion in court on your behalf.
$425 may seem like a big fine, but if paying it will make the difference between being hired because you have no criminal record and being rejected for a job because you have a criminal conviction for theft, such a payment is probably well worth it. But wait for now. If no criminal case is filed, do not pay the $425. Macy's will not sue you for it. It is too expensive for them to do so.