So now I get several calls a day from collections agencies. I usually just don’t answer because nobody I know has that number. Will they believe me if I say I don’t know who they’re looking?
Yes, and they’ll stop calling. When the debt goes to a new collection agency, it will start again.
Is there anybody you don’t like who has the same last name as this deadbeat?
You could give them that person’s name and phone number identifying them as a relative.
If you haven’t given it out, is it possible to request/get a new one from Verizon?
Supposedly they legally have to quit calling you. That doesn’t mean they will comply, and other agencies might call you as well.
Make a note of all the calls, and if you ever get more than one from a single agency, report their asses to the authorities.
You have to tell the debt collector in writing that you don’t want to be contacted again if you want to assert your rights under the (federal) FDCPA. See here.
My daughter’s first number belonged to a sex worker - the company happily changed it AND flagged the account as a do not re-use.
Waste of a perfectly good client base. 
Some asshole named “Petyr” went around handing out my number to young ladies, claiming it was his. They would call me, angry, drunk, stoned and/or heartbroken, looking for “Petyr”. And no, they would not believe I didn’t know who the hell he was!
So, “Petyr”, if you are out there - here’s a hearty curse. May they all catch up with you someday. 
Well, in retrospect, I imagine the guy who texted looking for a meet-up (and asked about cost/specific sex acts) was more than a little mortified when the police dropped in to see him and demanded to know why he was texting inappropriately with a minor. OOps
Happens all the time. At my last apartment, my land-line number had previously belonged to this Laotion guy and I’d get calls at all hours of the fucking day and night, for the entire five years I had the number.
I’ve had my current phone number for 3-4 years and I still occasionally get collection calls, friends calling and even random text messages for her.
Just the nature of the beast. I take comfort in knowing that random celebrities likely also get these sorts of calls. Justin Beiber being hassled by creditors looking for some random scumbag and not believing he’s not the person they want, for example.
Suppose you responded to nuisance calls, “Dammit, I’m Justin Beiber! Get off my damn phone, or I’ll have my lawyers sue your ass!”
This is what I’d do. Spin the wheel and hope for a better number.
I’d expect that my phone number would then be widely broadcast and I’d get a lot more unwanted calls.
Well, hell.
You know what your problem is, Chimera?
Your problem is that you confuse a guy with the facts, pal!
On the assumption that Fios is a VOIP-based phone service, sign up with Nomorobo.
I got this crap for years, almost always on my answering machine, so I wasn’t there to tell them to fuck off. For quite a while, my answering machine message was some variation on “If you are one of the many people apparently looking for [Deadbeat], there is no [Deadbeat] here, nor do I know anyone by that name. You have the wrong number. Please don’t call again. If you’re actually calling for me, feel free to leave a message.”
It eventually thinned them out so that I was only getting one or two calls for [Deadbeat] a week.
It’s amazing to me how long such things can go on. My husband has had his cell # for something like 13 years, and he still gets calls for the person who had it before him. Fortunately, it was a preacher, so the calls are fairly benign and the callers apologize. Still, all these years later, he still occasionally gets a call.
I changed my phone company and they gave me a new number which immediately starting getting calls from a collection agency. I had them transfer the number over from the old phone company, which I’d said I wanted done to start with.
I had problems with collection calls for the person who had my number previously.
The would NOT stop, no matter how many times I told them they had the wrong number and how many times I blocked their number.
It took getting a lawyer to make it stop.