No service at all and

I rented a car, when I returned it. They say there is a new scratch and its my fault. Luckily I took photos before I took the car as they never inspected the car with me also. After a long wait, eventually they could see that it is not my fault and will send me my refund. I received my Invoice and to date have not received my refund. I'm not happy about the invoice as I filled the car with fuel to the max and the garage is literary 500meters from the yard. now they invoice me for refill which is impossible but to wait for them to sort this now will take another 21days. This is so ridiculous. Today I phoned three times and sent an email and everyone says they will return my call but no one is returning my call. This is the worst service I have ever received from any of the car rental dealers!!!!