DELAY FROM THEIR SERV. PROV,BUT I HAVE TO PAY

I was in an accident with my car,and I then submitted a claim with my insurance-Discovery insure.On the assessment report that I received,it stated that the estimated repair time will be 12 working days, depending on avail. of parts.After 2 weeks that my car was with the repairer,I phoned them to get the status of my vehicle. They informed that they should receive parts today(04.03.16), and the repair will take AT LEAST 4 weeks after that. Exclude the 2 weeks waiting for parts-that is still another 4 weeks-what happened to repair estimate of 12days?I have no more free rental days left,and Discovery is not willing to pay for the extension of my rental car even though they chose the repairer-and that is where the delay is.Discovery informed that parts were on back order from VW,which is incorrect as I have just spoken to the repairer, and nothing is on back order, it took a week for the parts to be received, and the only ordered that parts 3 days after approval was received. Discovery's service is pathetic,and I will def. be moving my insurance elsewhere once this claim is resolved - if that will be happening anytime soon. Do not use Discovery insure-they must stick to Medical Aid!