Ask HN: How do you ask a similarly-named company to change theirs?

Hi HN,

I run a company that makes a product called e.g FooBar. We launched two years ago.

A company called BarFoo launched several months ago, selling services to the same market.

We're not competitors, but this has understandably caused some confusion - we got an email from one of our customers wondering about BarFoo, saying that "it seems like [BarFoo] is diluting or infringing on your outstanding Product".

I'd like to ask these guys to consider changing their name since we're older, more established, and as I understand it have dibs on the trademark (IANAL).

Anybody encounter asking another company to essentially change their name? How did you handle it?