I was also thinking that salesmen will cold-call/email me at least three times before they give up. People with whom I have no business relationship try harder than a corporation taking someone's money.
Welcome to modern economy. This applies to B2C, and as we can see it, B2B too. Getting a new customer is all the shitty vendors care about. Keeping existing customers is apparently just cost.
I ignore most of my vendor's emails because they're simply trying to spam me at this point.