[dudul]

Lego.

They have a service to order, for free - not even delivery fee, parts that you lost or broke.

A year or so ago my 6 year old son sent them a handwritten letter alongside a drawing of a castle. He was asking them to please bring back the castle theme, and if they didn't have any idea they could use his drawing for inspiration.

A few weeks later he received a response. The rep congratulated him for his drawing and told him that they used it for the set that they were just releasing - The Lion Knight Castle. The timing was excellent, but the rep was also very clever in their reply, making it very personal. You could tell someone took the time to sit down and figure out how to craft a response adequate to the original sender.