Factory Outlet Stores sent wrong merchandise and kept over $50 of my refund Internet

I ordered a pet product online and selected the size.  I then went the shopping cart to purchase but a pop up ad came on for a bundle deal and I chose to add it to my cart. Upon doing this it changed the size of my product with out me knowing it.  When I recieved the product I tried to exchange it but could get know help via phone or email over a 2 week period.  I went online and got an RMA to return the merchandise.  I paid to ship it back and when they eventually refunded my money it was short $50 for "restocking and shipping". First of all I paid to ship it back and it was free shipping. I urge everyone to be very careful when dealing with this company they are very underhanded and shaded with their products.  When I called to speak with someone the lady told me NO she would not refund and there is nothing I can do about it!