I'm not suggesting govt. get involved but if an FBI agent can find someone who, for instance, made a threat to a judicial branch or individual they would already have that person in jail.  Phone companies say they cannot do anything about this.  Not true.  They can but it's costly.  I work in a computer communications world.  "Everything is Trackable".  Even the IRS scandal.  They know but WILL Not do anything about it for political reasons.

I'm not sure there is a best way to handle this on your own but when home I do answer the phone with hopes to get a live person.  Once in a while I do.  I will drill them with questions and even ask for their number for verification or that I will call them back.  Sometimes I will ask for their main office number to verify who they are.  

If they give you a fake number, ask them if it's their own.  If they say no, ask them for theirs.  Hey, they have yours, they just called you.  If they refuse and say they cannot, that is BS also.  Their personal phone is their property and they can give it out to whom ever they wish.  Call them on it.  Tell them you want the ability to call them while they are at home eating dinner or watching TV.  Even in the middle of the night just to say HI....  They usually hang up.  If they don't, I just tell them they are a worthless piece of flesh or something along those lines.

I have even been threatened by some of these soliciting companies.  I welcome it and tell them to bring it on, you are pretty tough over the phone, lets see you face to face.  Let me have your number so we can arrange a time.  Then they usually hang up.

called i did not answer, they left no message,  so i guess it was nothing important.

Caller name shows as a number 12097828675. We do not know anyone with that number nor do we know anyone in that area code. Whenever a call comes in that we do not recognize as one of our regular contacts, we just look at the caller id and ignore.
Later, we go into our Verizon settings and add the number to the call block list.One of the problems that allows people to get scammed by crooks is that one should remember that if you have not entered into any sweepstakes, or applied for any credit, or shopped at any store (whether online, or in person) where you applied for their card or gave your email or phone number, then you are going to be scammed, spammed, and/or conned, for maybe all of the above.
        
The rule of thumb is that you know whether or not you have requested contact with the number that is calling or not.  If it is not family, work, business related, emergency from your doctor or hospital, "Do not pick up" or answer.
        
When you answer the phone, you are confirming that your phone number is a valid number.  When you select the option in an email for them to remove your name from their list, this allows them to remove your name from one of their lists and pass you on to another of their lists or list of associates.  In other words, you are setting yourself up for indefinite contact from a multitude of partners. If ignored, eventually they will go away.  It may even take up to a year, but eventually they do go away, because your phone number of email is not a prospective investment of their time.

Said they were from card services, trying to lower my rates, seemed like a phishing scheme to me. My credit card company said they don't hire any companies to lower my rates. Don't give them any info.

I get them too. IMHO blacklisting (either with a call blocker or blocking service) isn't very effective. The scammers can morph the caller-id number you see into many more than most devices or services can handle.
My approach is to whitelist; my call blocker blocks every call from a number that I have not explicitly allowed.
I only get calls from family, friends, and work. I'l still working on the last one :)