You Always Have a Choice. Always.
A) You Could Look Down or Dislike them OR
Why would you thank them? Because it tells you that YOU are doing something right - coz you dont know who the F they are, but they seem to know who YOU are.
Say thank you - no matter what (recognize who they are, for what they are - but MASTER “how” you choose to respond). That’s #Mastery right there. It will further accelerate their jealously and burn them in their own fire — you dont have to do anything. That’s a huge Win, I would think.
And dont worry about what they might do to defame you. Most people are Smart and Can / Will see through them, and be pulled even closer to you - Those are your people.
Those that are easily swayed — they dont belong in your circle. Kick them to the curb (the Jealousy is helping you with this as well). So this is why I say - Say Thank You!
LIVE YOUR LIFE!