Stop robocalls

Have had this number plus other numbers starting with 0480 012 ending with different numbers everyday for the past week and a half. Have not answered anytime, my phone showed it as a potential fraud call. Googled the numbers each time to be met with results with users also stating it being a scam service and negative responses. Have called back a couple of the numbers, with my phone number on private, to have someone pick up and asking in a foreign accent trying to sound american "who am i speak