That is a tough situation to be in. Wisconsin has adopted the statute of frauds which basically states that all contracts for more than one year, or dealing with real property, must be in writing. Your verbal contract violates the statute of frauds both ways. There needs to be a few more facts, and there may be items in writing that you didn't think of that could satisfy the statute of frauds, and then the oral agreement could be used as parole evidence to clarify the details of the transaction. Really you need to go see an attorney with all of the paperwork (if any) and anything else you have that might go to show that you have "equitable title" in the property and thus have standing to file suit. A face to face consultation with all of the information available is the only way to find out the potential merits of your claim.
This is not legal advice, and is just general information. I am not your attorney.