Questão jurídica principal
Whether the default notice under Art. 257d CO was validly notified to the tenant
Decisão extraída
No. Because the notice of collection for the registered letter was not proven to have entered the tenant's sphere of influence, the registered notice was not deemed received; the plain-mail resend did not cure this defect.
Fundamentação extraída
The landlord bears the burden of proving receipt. The presumption of receipt for registered mail applies only if a proper collection notice was deposited in the recipient's mailbox or postal box. Since that was doubtful, receipt could not be assumed.