Questione giuridica chiave
Whether the federal appeal was admissible despite non-payment of the advance costs within the deadline.
Decisione estratta
The appeal could not be heard because the appellant neither paid the advance costs nor provided the required proof of timely payment.
Motivazione estratta
After a formal warning under Art. 62(3) BGG, non-compliance with the non-extendable deadline leads to non-entry under Art. 108(1)(a) BGG.