Iwyze not willing to pay for repairs

Had an accident on the 7th May 2018 and my car was written off because repair cost were greater than the value of the car. Then i inquired if the insurance can pay repair cost if i got a panel beater that could repair my car at a lower cost than their inspectors quoted. They agreed, I then requested to get the car to the panel beater that I got. Now Iwyze is refusing to pay, saying I took the car and there's nothing they can do. It's either I give back the car and they pay me the value of the car or I fix the car myself without their involvement. I have not defaulted any payments, I have 2 cars and a house insured with Iwyze. The call centre agent was rude and they not coming up with a concrete solution on this matter. I am advised to go the legal way on these matter. I am very unhappy, now my petrol pump is missing because my car was parked at their panel beater.