Gather ALL information you have dealing with this transaction. I also hope you got proof of mailing and proof of the person receiving the returned product. If you do, then call your bank and start a fraud dispute.
You have to wait 30 days from the date they received the returned product to issue a credit. I know it sucks, but it's the rules in the banking disputes world.
Hint: Sometimes if you raise enough 'youknowwhat' and get the senior manager into it, they will just give you the money. This woman's daughter went on a shopping spree with their joint bank account card, we had her signature and VIDEO of her buying the thousands of dollars worth of clothing. All the proof was there, I removed the temporary credit. However, the woman was such a pain in the rear, they let her keep the credit to make her stop bothering the bank!
I dealt with hundreds of these things at citizen's bank here in Mass.
If you do not get a credit in 30 days and followed all the terms of returning/refusing the products and services, the bank will then credit your account for the funds and go after the company. They will be doing a 'chargeback'. The process is usually 90-120 days long. If at the end they get the money, the credit to your account will be permanent. If the company proves you didn't follow directions (this one is sometimes hard for them to do) then the money is yours. If they prove you were wrong (usually doesn't happen, unless it's internet porn site charges) then the credit will be reversed.
Good luck and be more careful in the future.
Try using credit cards for online purchases. Credit cards have WAY more fraud protection than bank cards.
Even if a bank card has Visa/Mastercard logos...they don't have the same protection as credit cards!