Questione giuridica chiave
Whether the appeal was filed on time by proof of postal submission
Decisione estratta
The appellant did not prove timely submission of the appeal; the cantonal court's finding was not arbitrary.
Motivazione estratta
The appellant bore the burden of proving timely filing. The court could reasonably distrust the late, unspecific, and internally problematic witness confirmations and the unusual way the letter was posted.