Jack is a licensed real estate agent.  Sally must leave immediately for a new job overseas and enters into a written agreement with Jack for him to sell her townhouse in Subiaco for the best price obtainable within one month.  She tells Jack that she wants to receive net proceeds of approximately $125,000 after paying Jack's 4% commission.  Since Sally will be outside the country, Sally instructs Jack to "tidy up the townhouse and gardens", and Jack is also authorised to enter into the transaction on behalf of Sally.  Jack is given a power-of-attorney so that he can sign any land transfer documents on Sally's behalf.  The townhouse is put on the market for $135,000 after Jack pays out $640 for some painting and garden work.  Jack knows that Eric is willing to pay $135,000 within the month but he tells Eric that he will persuade Sally to sell for $130,000 if Eric will pay him $2,500 "under the table".  Eric agrees and buys the townhouse.  However, Sally subsequently finds out about Jack's agreement with Eric. Sally is furious and refuses to pay him his commission, and tells Jack that she is going to report him to the police.

Advise Sally on her position and all potential remedies.