Did not receive a part and they are charging for i...

Did not receive a part and they are charging for it.

I placed and order "R701048878" and I never received complete order and there was a missing part. I called service desk and they sent an item which didn't fit my car. I called again service desk and gave my car VIN number then they said they don't have a right part in stock and asked me to send the item back. After returning the item, they are not giving refund if I ask for refund they say it was a replacement order so no refund. Okay! I didn't get the part in my original order so they sent it and now that didn't fit I am returning the part shouldn't I get refund for it? How can they charge for the part I didn't receive? I never expected this from them.