How To File A Complaint

made a reservation online when arrived to pick up car i was told that i couldnt use my credit card cause it had a h&r block on it which it  is a mastercard i was told they couldnt accept it when i had rented two vechiles the prior months with the same credit card and it wasn't a problem i called and spoke to a supervisor and i was told to call the local manager at that location and he didn't even answer my call left my number he didn't return my call i tried several times afterwards still didn;t speak to no one