Expired Chocolate

On the 5th of March 2019, I purchashed an 80g slab of Cadbury Cashew & Coconut chocolate. Upon returning home, I noticed that the slab had passed it's best before date. I took it back to the store I purchased it from & was told " it is not their fault as they only pack stock onto the shelves" & "I must contact Cadbury directly. I sent an email to Cadbury but received no response. If expired products are being sold to the public, how long will it be before someone falls ill or worse, dies because of eating something like this?