How to block incoming calls for personal loans/credit cards?

I keep getting calls everyday for personal loans or credit cards (mainly Axis). I have never subscribed to any of these alerts. At this point, it's very frustrating cause they keep calling from different numbers and it's impossible to block all of them. Even if you block 100s of numbers, they'll have a new one that still calls you. Is there any way to avoid these calls? How effective is Truecaller?