They won't listen and there's not much you can do. They are a bill collector and if you tell them to not call you they just put your number on the call twice as much list...
I think that answering the phone and telling them that no one by that name lives there. Be firm. Tell them you don't know anyone by that name. They should eventually stop calling.
Your legal name is your married name so no one lives there by that name. It is someone's old name but not anyone's current name. So one with that name exists anymore.....a bit of a fudge of the truth but not an out and out lie.
you can also act like it is you then sound all Oh wow, someone really did that???? I can't believe a person would really not pay a bill like that.
The more you make it sound like you were just telling them that was you so they would tell confidential information the more they will decide this is a wrong number. PLUS you get to find out about what the bill is about without committing to it being you they are trying to get hold of.
This may be some long lost bill that you did pay off but they lost the accounting of it. That does happen. I always tell everyone who pays their bill at work that even though they used a check or credit care, and especially if they pay with cash, that they need to keep their receipts just in case...no one is perfect and they do lose checks or paid in full stamped bills.