bad customer service new balance Canal walk

I am very furious with New balance manager at Canal Walk I had to wait more then 15 minutes for a manager the lady assistant had to go call him as he left his phone. On top of it now when I want to do a exchange he said it's outside the 7 days policy for return but I can exchange but I must match the value or buy other things as he can't give me a voucher. I asked him where does it show in their policy that I must match the value of the return as it does not show that on the terms and conditions at the store policy he read he says that is just a policy. Please I need this resolved as bought items worth 6 000 my husband has the right to change his mind.