Help: Got Defrauded Of N380,000 By A Gen Customer

My younger brother was defrauded of N380,000 by a customer with name Barr Ajaebu on invoice, who bought power Generating set from him on 31/05/2024 in Aba, The customer did a transfer and left with the Gen after dropping his number(08166017425), the credit Alert hasn't been seen and since then, he is not responding to calls or replying texts, His number is currently switched off but seems active on whatsapp. Please any idea on how to track this Guy and get him to pay.Your help on this will be appreciated