Samsung Galaxy Note 4 — Unwanted calls

I have had this Note 4 Samsung phone for a few years, there must be a way to block unwanted phone calls from credit card companies, and other offers....I had two calls today from card company offering to reduce my credit card interest. I don't carry credit card balances and the message asks for me to press "9" to connect with operator. I did and told the overseas call center, that I did not want these calls and he hung up. I guess its time to purchase an app in order to stop these annoying calls. Does any Note 4 user know of an app to stop or block unwanted phone nos.?