Harassment from Planet Fitness sales staff

So after finding the information I needed from the internet, the sales consultant doing their due diligence called me to see if I was interested in taking out a contract. I informed him I was just doing some research and that IF I was interested I would then contact them to take out a membership that he should please remove my information from their system as I don't want to be inundated with calls.

Since then I have had 3 more calls from them and each time I have told them the same thing and that they must remove my information from their system and yet I still get calls.

This is now harassment and I am very tempted to now take legal action should this continue