Hello Chochybear,

If the bill you have received is related to the local Tax ( IBI ), I am afraid this tax does not expire, so you need to pay it, regardless of you having not received the bill at home, as when you buy a house that Tax is compulsory and if you do not receive the notifications, you need to claim them at the Town Hall.

The 4 years expiration you mention is related to the Non resident Income Tax unless the prescription had been broken at any time during that period after having been notified.

Regards,