damaged replacement power antenna

I wish to file a complaint about Auto Parts store (autopartsgiant.com)

I purchased a replacement power antenna from these guys which to forever to get only to find it was damaged when I received it. The way it was packed obviously indicated it was packed damaged. It wasn't damaged in shipping. I called and they gave me a run around. Finally someone on the other end gave me a return number which I did at my own expense. Now they cotacted me saying they will credit my credit card minus a 20% restocking fee. There is no way they should be restocking this part. Then they suggested I probably broke the part trying to install it. I couldn't beleive it!!!. Buyer beware if your considering buying from these people.