Money not reflecting after depositing

I’m Very disappointed,because I believe when you deposit the money it should reflect immediately.it was my first time depositing and needed the money immediately but to my surprise when I get to Avis paying for a car rental it declined and I called and they told me it takes few hours and I needed the car for me to leave early Friday morning and I stayed there until they closed at six and the money didn’t reflect.so please fix your system