Stop spam calls

Trading platform (so they say) scammers who do not take No for answer. Have asked to be removed from their call list hundreds of times (not an exaggeration) but they refuse and call from different numbers. This has been going on since August (reporting near end of November). I believe they are based abroad although they use UK landline and mobile numbers. They abuse you verbally and have also impersonated my bank's fraud department. People should not have to change their telephone numbers i