Here's what *you* have to understand about what *they* are hearing in the call center. You said "not interested". You did not say to stop calling. You did not request the addition of your number to an internal no-call list. You did not secure a mailing address so you can follow up with a cease-comm notice, best sent via USPS Certified with return card.
If you are not specific about what you want, and end to the calls, it's assumed that with enough tries someone will get you "interested". At some call centers the reps are *ordered* not to accept a no-call demand unless it's phrased correctly. Thus, "take me off the list" is wrong. The caller may not have any target list to begin with. To remain in legal compliance, a sales caller must ADD your number to an internal list on request. Your name and address is not needed, only a number.
Much of this assumes the caller is actually concerned about staying legal and not just another offshore scam outfit. In such a case, our laws do no good and you'll have to fall back on less reliable blocking strategies.