Avis Car Rentals and Discovery Bank! Stay away

My insurance hired a car on my behalf as curtasy car on the 24th of February, a holding fee was paid then the car was released to me, I returned the car on the 31st of March and I was told that my balance will update after 7 days, that hasn't happened!I called and spoke to a customer service agent on the 7th of April and they advised that the funds had been released,I called my bank: Discovery bank on the same day and they informed me that they couldn't trace the funds,I called AVIS again and they informed me that the money has been released. To this day I haven't received the funds! Discovery bank keeps saying they are investigating! What kind of investigation goes over 50 days (without an update?)

Can this matter get sorted?

I wouldn't advise anyone to trust both parties with their money!