That was kind of them as accidental damage isn't covered by a guarantee. Of course, if it was insured that would be different.
I worked in customer service and we wouldn't have exchanged, refunded or repaired an item that was damaged by the customer. Most guarantees are for a minimum of one year, so would have offered a refund or exchange for the faulty light though, as a repair would be too costly. And yes, we offered refunds and exchanges beyond the legal minimum.
On that note, many years ago, a customer brought back a brush head for a refund (no receipt). She didn't take well to this being refused. We likely would have offered a voucher or exchange, if it wasn't for the fact that we didn't sell that item. She attacked my colleague with it. My colleague raised her hand to protect herself and ended up in A&E. Luckily her hand was bruised but no broken bones.