MiWay Insurance was my bad move for car insurance from Discovery Insurance

My car was bumped into on the 16 June 2018 whiles I was busy shopping at an Engen Petrol station. My car was bumped into and the perpetrators drove away but was caught. I made in insurance claim with MiWay Insurance and my car was taken for repairs. Only the back part was repaired but when I asked why they say the other dent is old. They gave me a courtesy car for 30 days that should end on the 22 August 2018 (this coming Wednesday) but suddenly I get an sms from Avis stating that I should return their car on the 17/08/2018 late on the 16th of September 2018. No one is communicating and calling me about the other dent that should be fixed and they claim it's their management who took that decision.