Sounds like a letter they send to shoplifters. If you "google" the number 800-236-7428 you will find many instances involving this. If it is not you, they may have an error in your social security number or driver license number, which they got from the true defendant.
If you need representation, call us at (530) 758-8317 or email firstname.lastname@example.org Our replies to Avvo questions should not be considered specific legal advice to any individual, and no attorney-client relationship is formed with you. Our aim is to provide general principles that may be useful to the Avvo community as a whole. You should seek individual legal advice pertaining to your specific factual situation, and the laws applicable to your jurisdiction. If you want that advice from us, contact us at email@example.com.
I agree with my colleague.
I would add that if you have not had any adverse dealings with Walmart (particularly shoplifting), you may consider calling the attorney mentioned in the letter to inform them of the mistake.
Be aware that talking to an adverse attorney without an attorney of your own can be dangerous, so you should strongly consider having a local attorney make this call for you.
However, not making the call could leave the other attorney to continue pursuing a claim against you and the next paper you receive could be served to you by a Sheriff Deputy.