sold a business model was a lemon , old owner new come to find out is there any course of action

If the former owner made material misrepresentations to you regarding the track record of the business, its foundation and business model, you may have grounds for suit to recover your money from the seller.  There are really two different claims with two different quantum of damages which litigants pursue in your circumstances: breach of contract and misrepresentation.  You should consult with counsel to review the specific terms of the Agreement and representations which were made to you in soliciting for this business venture.