Once you have the form, you are just going to fill out and make an excuse like the chocolate stunk of poo even though it was in it's use by date.
Make sure you say you purchased it from a big brands such as Walmart, Tescos, Sainsburies etc etc.
You will then get an email back sometimes same day or next day with some coupon codes which lets you buy double what you had most of the time.
Sometimes they want some pictures just say you chucked it in the bin but have pictures of the barcode and then send the pictures I told you to take earlier.
Enjoy your free chocolate and please don't leach my post.