Three suggestions

One, go to small claims court. An oral contract is a valid contract. Therefor, she broke the contract. You should be able to get your money back. However, the amount in dispute may be only $200, which may nto worth the trouble. So here comes the second suggestion.

Two, write a letter to IRS, with detailed information on the person's name, contact details and report that you are well aware of the fact that he/she under report their income tax.

Three, call her one last time and threat to report to IRS and take her to small claims court.

But be careful about recording conversations with your answer machine. It could be illegal in your state.