CALCULATION FAULT WESTBANK

I had a motor vehicle accident in April 2018 and after sending a settlement quote letter to my insurer and after my insurer has paid out based on calculations made on the settlement quote letter received from Wesbank, we received a letter with a TOTALLY different settlement amount on as that that was given to my insurer. How is it possible that the settlement amounts differs with almost more than R5 000.00 after my insurer already paid on the settlement quote letter provided in the first time. The Settlement amount on both letters forwarded to my insurer and to myself has to be obviously the same then with calculation as payments received from the insurer. The consultant from the Wesbank stated in her e-mail that she does not understand my debate...! SEROUSLY!!