Okay people, here's what you do. when you get a call from a number you do not know, DON'T ANSWER IT! If you answer it, your phone number gets recorded as a legit number and you'll start getting calls from a lot more numbers you don't know. That's why these call robots exist, they sell phone numbers that have been verified to other scammers in bulk.
What you do when you get a call from an unknown number is check this site. If a bunch of people have said "I answered and they hung up right away" or "scam" or whatever, then just go to your mobile carrier's website and block the number. It's that simple.
I don't know how other carriers work, but with Sprint you'd log in and go to preferences and then click block voice. Select your phone, type in the number, hit save at the bottom and boom. Done. I currently have 28 numbers on my block list. Every one of them I checked on this site first and every one of them is a scam or a callbot.
The reason these callbots and scams exist is because it is not financially beneficial for phone companies to stop them. This will never end, so learn how to deal with it intelligently.
Got the same call as everyone else, some comany selling a lower rate on my credit debt. They called my cell and for some reason that really pisses me off. "Heather" didn't respond when I asked if she was an actual person so I hung up. My mistake was picking up in the first place!
Got a call 10 minutes ago. Automated message about my visa card. I clicked for a live operator, got a very detached woman on the other end. She tried to trick me. I said "is this about a credit card I have with you?" "Yes sir, you have a visa card right?" I almost said yes, but then I remembered that (A) I dont have one currently, but (B) this is none of their business. I told them anyways - "no i do not currently have a visa card". She goes "you don't have a credit card with over 3000 dollars in debt on it?" "No, -" I started with the intention to tell them to remove me, but she did an instant hang up, no further discussion. I don't think they would have taken me off their list anyways.