Question about Gigaset C570A Go

Callers can be blocked (but this function is generally not much help against advertising calls, as these crooks change their numbers more often than others change their clothes). There is also an answering machine. Now, in my view, this device with VoIP functionality is aimed more at people with an affinity for technology; if the focus is on ease of use (for older people), there are other options, e.g. the Gigaset E290A.

You can add numbers to the barred list under "Settings", under "Do not disturb", under "Barred list". However, this requires a little technical flair. Otherwise, it is relatively easy to use and install.