Refund 30% admin fee

Hy I need help. If you was returning products and wanting refund for the products that you're returning and they then tell you that you will be deducted 30% from your refund but the section in the policy that they referred you to they didn't mentioned anything about the 30% admin fee, where can I really go to get help because I even consulted to a lawyer and he said that they didn't mentioned it in the policy.