You can downgrade to Wanadoo pay as you go, and just by logging in to get your emails will keep your account active. They will suspend you after 90 days but even then you can still reactivate your email.
I went the other way, from Tiscali to Wanadoo and still get my Tiscali emails as well as my Wanadoo ones.
I don't pay Tiscali anything any more. The changeover was smooth and now I am just paying for WanadooBB.