No billings found, checking schema...
  - id (bigint unsigned)
  - tenant_id (bigint unsigned)
  - client_id (bigint unsigned)
  - meter_reading_id (bigint unsigned)
  - billing_number (varchar(255))
  - previous_reading (decimal(10,2))
  - current_reading (decimal(10,2))
  - units_consumed (decimal(10,2))
  - subtotal (decimal(12,2))
  - tax (decimal(12,2))
  - other_charges (decimal(12,2))
  - penalties (decimal(12,2))
  - total_amount_due (decimal(12,2))
  - amount_paid (decimal(12,2))
  - balance (decimal(12,2))
  - billing_date (datetime)
  - due_date (datetime)
  - status (enum('draft','sent','overdue','paid','cancelled'))
  - remarks (text)
  - created_at (timestamp)
  - updated_at (timestamp)