Woodford Car Hire Nightmare

Rented a vehicle on the 20th of March, returned vehicle in 3 days, my rental deposit was supposed to take 10 working days, guess what? It's nearly a month waiting, when I called to enquire about the refund for the deposit on the 11th of April, I was told it was not processed and they will inform their head office. Today is the 17th and still nothing. I cannot use my credit card, my credit score was affected and all I am getting is " we are sorry for the inconvenience caused" wow.. why is something so simple to do, has to take that long to sort out?