I placed an order and they sent me a wrong order

I placed an order and they sent me a wrong order. I told them about it and they send I must send theirs first and then I will get mine after they received theirs and observed it. So I told them that's not a mutual agreement I have customers that ordered and waiting for their orders so I can't wait another week or so. They can send mine while I also send theirs back because I am not the one at fault. Now they are telling me I can do whatever I want. They don't care