There is no point trying to block the numbers as they are usually fake and they change for each call. It would be an impossible task to try to keep blocking them. There are pretty much no useful features on the VM landline to block nuisance calls in this situation.
Instead take a look at call screening devices such as trueCall or the BT Premium range of cordless phones which incorporate trueCall technology. These filter and screen the calls for you then decide whether to allow your phone to ring or not. Silent calls and other automated scam calls are screened out and rejected by the device and your home phone remains silent.
