$1,800 for a 3 min email is a bit odd.
As far as I know, if you remove their content, or give them credit for it, they can't sue you for copyright, as they are posting the information on a public venue.
You should just give them credit, and be done.
If the company is that hard up for money, they will want you to pay the $1,800 so they can bank off of it. I can't see them investing more than a hour into getting your information, writing out a letter, and mailing it.
Also, if you are not in the same country as them, i wouldn't worry about it.
As far as I know, if you remove their content, or give them credit for it, they can't sue you for copyright, as they are posting the information on a public venue.
You should just give them credit, and be done.
If the company is that hard up for money, they will want you to pay the $1,800 so they can bank off of it. I can't see them investing more than a hour into getting your information, writing out a letter, and mailing it.
Also, if you are not in the same country as them, i wouldn't worry about it.