Wheeling with new wheels

"Advocacy is the best policy." I know that's not how the phrase goes but in my case I must alter it. I got an oil, lube, filter recently; I can only go where they have a long window to look up at the bottom of the vehicle cause I won't drive it on a lift. I must drive my own vehicle always since a Dodge dealer crashed it into a work bench. So after the initial service I ask for windshield wipers since mine were no good. The man took my debit card and came back with the wipers and card. He then took one look at my situation and said he couldn't install one because the arm is bent then he did the other even though that arm was bent too. I asked for my money back two times and he gave me $9.00. So essentially one wiper cost me 14.63 since he said installation makes it cost more. I called the company in Covington Kentucky in case I wanted to report him. They offered me a refund of $11.99 and said they weren't allowed to charge me an installation fee.