You can reduce the number of spam/sales calls by registering with the Telephone Preference Service by phone on 0345 070 0707 or online at www.tpsonline.org.uk.
Any UK company that continues to call you can be reported via the TPS website and if they still continue to call you can report them to the Information Commissioners Office which has the power to prosecute any company that continues to make unwanted calls.
Silent calls come from an automated calling system used by many sales companies where there is no operator available to speak to you after the call has been automatically dialled, these can be reported to Ofcom on www.ofcom.org.uk.
If you receive an abusive or threatening call this can be reported to the BT Nuisance Call Advice line on 0800 661 441 you can also report these calls to the Police by dialling 101 and giving as much details as possible so that the Police can attempt to trace the call.
Registering with the Mailing Preference Service
The Mailing Preference Service supports the right to choose the mail you wish to receive. Registration to this free service can be made on line or by phone to 020 7291 3310. Registration can also can be obtained from www.mpsonline.org.uk.