Car computer exchange Will not give me full refund when it was their mistake Internet

 I have ordered a car computer from this company for my 1994 Chrysler Sebring convertible. They sent me the 1 st one and it was the wrong one. I sent it back and they sent me a 2 nd one. Wrong one again. Again I sent it back with pictures of the correct one enclosed. Again I received a 3 rd computer and you guessed it, wrong one again. I sent it back and asked for a full refund. They said no problem. I got the refund today and it was for less than half of what I paid for the computer. They replied something about restocking fees and such. Why should I have to pay these fees when it was not my fault that they kept sending me the totally wrong computer. DO NOT BUY from this company.