If it is really a big deal, then send a copy of the mailing back, and ask to be removed. If they do not comply, send a copy of that letter asking to be removed, and a copy of the letter to the better business bureau.
Here is what I did for my unwanted mail, I attached a second mailbox to my house underneath my first. I wrote on the top mailbox (mail addressed to “stated my name”). The second mailbox underneath, I had cut out the bottom portion. This one I labeled (mail addressed to “resident residing at”). Underneath the mailbox with the hole, I put the trash receptacle I keep on my porch. All junk mail quickly falls into that can, and the mailman got a good chuckle.
You can just throw this junk away then and there, as you get the mail.
Well, this is from AARP, but there are some good ideas here. Wish I had found this earlier. I did it the hard way, by writing on the return cards with a black marking pen, asking not to receive any more. It took a few times, but I don’t get mail from credit card companies anymore, and it has decreased.
Good luck.