I have a product that is licensed and hold a 14 yr design patent and I just saw a small business selling this product. What should I do? What type of notice should o give them?
Matthew Haugen is right. You need to contact an attorney in this case.
You should first purchase one infringing item, review the claims of your patent, and review if the product indeed infringe on your patent. It's important because you may find the claims in the actual granted patent were too narrow, or the competitor had circumvented your patent claims. You should also at least get the attorney/agent that drafted your patent application to give you an opinion on the strength of your infringement claim.
You should also discuss the matter with a litigation attorney. It's not advised to send a notice letter yourself, because if it's not drafted correctly, the other party can sue you first and put you in an unfavorable position.