Translation of "warrantee" into Greek

No no I know that the warrantee is expired, but isn't it supposed to last longer than two years, if it isn't effective?

Το ξέρω ότι έληξε η εγγύηση, αλλά δεν υποτίθεται ότι παρατείνεται αν δεν είναι αποτελεσματικό;