Unhappy customer

I'm unhappy with the way that Discovery handled my claim.They took more than a month to settle my claim.I received an sms today that the amount due to me is paid into my bank account ,however it has not cleared into my account.Now they are refusing extension on the car hire.how can I put a deposit on a new car if the money has not cleared.The rental car is due to taken back 2018/05/07. It's really frustrating that they refuse to give me atleast until Friday 2018/05/11 to get my things sorted out.