Proof of collection my #@&

I'v never felt so disappointed with a company in my life. iv returned a product and to this i did not receive refund or exchange for it...i called sent emails what i get is an email saying they need proof of the collection.. Is it that hard to find the driver who took the pfoduct.. Because he did not give me anything.. I'll ask for camera footage on that date at my workplace and it will not just be refund for that product.. If that person who collected that product thinks he is smart he has another thing coming