Contacting a sales department at their provided address for that purpose is responding to a request for you to do so. This is nothing at all like taking money to propagandize people.
Putting a product at a prominent part of your store because you think it's a good purchase for customers is also completely different from accepting money from a manufacturer to place it prominently.
Going to an event where everyone specifically went to meet and exchange information about what people in their industry are doing is also again entirely unlike paid promotion.
