I have got to believe this would be a small claims action. Whether it is worth it to you depends on the costs, the time involved, and the ability to collect, if you win a judgment. On the limited facts provided, it would appear that you have a solid case. But if you win the case and cannot collect, then you would not only lose your initial investment, but also the court costs involved with the small claims case.
I am licensed to practice law in the State of Michigan and have offices in Wayne and Ingham Counties. My practice is focused in the areas of estate planning and probate administration. I am ethically required to state that the above answer does not create an attorney/client relationship. These responses should be considered general legal education and are intended to provide general information about the question asked. Frequently, the question does not include important facts that, if known, could significantly change the answer. Information provided on this site should not be used as a substitute for competent legal advice from a licensed attorney that practices in the subject area in your state. The law changes frequently and varies from state to state.
It is unclear whether the person selling the soap was legitimate. Recently there was a story about a black market trade in TIDE detergent. This just does not smell right you may want to go to the police about this matter.
If you wish to go to court bear in mind you may not win if you have unclean hands. If there is no concern then this most likely is small claims action which you can handle on your own
I am only admitted to the MI bar therefore this is only general advice it is highly recommended to contact an attorney in your area for definitive guidance. Any advice given does not create an attorney-client relationship.