Margiknot,
you don't have to get rid of the land-line to avoid scam calls.
i have not had any scam calls since i bought BT call guardian hand sets.
i got them from robert dyas, but they are widely available elsewhere.
and you don't have to be a BT customer.
the magic is in the handset, there is no subscription fee, as long as you have caller ID, which nearly everyone does now.
unknown callers are intercepted and asked to identify themselves, which you then hear and can accept or not.
then you can choose to always, or never accept that caller, or continue to decide each time they ring.