Welcome, Newbie!

Congratulations - you confirmed that your number is legit so they can sell it to others.

Never ever use a "remove from list" or "unsubscribe" function when you get spam calls or emails, it will actually increase the spam/calls you get.

Congratulations - you'll now get even more scam calls!  

You could have just as well have answered when they called.  Aside from scammnig you directly, they're also after valid phone numbers.  So, whether you'd answered the phone or called them back to remove your number from their list, you've let them know that your is a valid number that they can continue to call or that they can include in lists of valid numbers they sell to other scammers

Rules of thumb to attempt to minimize scammer phone calls:
1) DON'T ANSWER CALLS FROM NUMBERS OR ORGANIZATIONS YOU DON'T KNOW OR CAN'T VERIFY
2) NEVER, EVER ASK TO BE REMOVED FROM THEIR LIST (if you make the mistake of answering in the first place), and
3) NEVER, EVER CALL THESE NUMBERS BACK FOR ANY REASON

As long as your answering machine comes on they know they have an active no.. When I see a no. I don't recognize, I immediately turn off my answering machine .... the phone rings up to 4 times, rarely more than 5 & then stops. This has been the most effective method for me. These scammers have electronic devices that by-pass the "don't call"  lists. Indeed, many are not even in his country.

That's a great idea to turn off the answering machine when they call!