We don’t offer call blocking features on specific telephone numbers as part of a Truespeed service at present.
Some DECT cordless phones come with a built-in call blocking feature or ‘Call Guardian’. This gives you full control over incoming calls, the ability to confirm known callers, block nuisance calls and vet everything else.
We’d also recommend looking at the Telephone Preference Service. It’s a free service that gives you the ability to register and confirm that you don’t want to unsolicited sales and marketing telephone calls. More info on this service can be found here: https://www.tpsonline.org.uk/