Stopping unwanted callers.
People you wish didn’t have your number. Companies trying to sell you things. Scammers. People you can block on your phone, if they persist with new numbers, that’s harassment so get the police involved.
Stop telemarketers by using free Telephone Preference Service (0345 070 0707). If they persist take their details and report them. Scammers? Talk to your phone company and consider an app. Never give out private details in unsolicited calls, whoever they say they are.