Jeffrey bought a three-bedroom house in Plattekloof. However, the roof needs some repairs before him, and his family can move in. Jeffrey contacts Rory Contractors (Pty) Ltd who is willing to do the repairs on the roof for R20 000. Jeffrey has already paid R10 000 to Rory Contractors as they have completed half of the repairs. The other half of the money, the remaining R10 000, will only be paid to Rory Contractors once they have completed all the repairs. However, Rory Contractors is already demanding the other half of the payment, even though they have not completed the rest of the repairs yet. Jeffrey would like to prevent Rory Contractors from claiming the rest of the payment until they have completed the repairs. Required: Identify and discuss the most appropriate remedy that Jeffrey can use to secure perform from Rory Contractors (Pty) Ltd in terms of the agreement.