Bad service, no payment

We are Goedehoop Guesthouse from Zeerust. Thendo (a consultant for Duma Travel) made a booking for Mainganye Mashudu via email. Thendo was supposed to send the proof of payment before the guest arrived. However, no proof of payment was received and guest had to be booked since the guest had a conformation sms that the booking was made successful. Thendo is not replying emails (however Thendo is active on his email) and Thendo is not answering the telephone.