Oops, forgot the link: http://www.wcaconsent.com/FAQS.html
They say that you will receive one more call to confirm your removal, but I won't answer that either. You have to give your name and phone number to opt out. They already have the number, and just try putting in any name you can think of.
That link is a trick set up by the WCA fraudsters to harvest more information from their victims.
DO NOT GO TO SCAMMER WEBSITES -- it won't stop the calls anyway, it'll just be additional confirmation about you and your phone number. Think about it -- why would you have to "opt out" of something you never opted into in the first place???
Complain instead. If there are enough complaints, maybe this criminal operation can be shut down and the crooks who run it held accountable.