Call customer services and they'll put on ACR (Anonymous Caller Reject) for you if ur have nuisance calls and it's usually free for a month only other alternative is for a number change. If these companies are still getting through take down the telephone number that has called via 1471 and go on this site:
http://whocallsme.com/
enter the phone number and search and when you find out who they are call them ... they don't like it when you call their head office to complain :-)