Key legal question
Whether the federal appeal was admissible despite non-payment of the advance costs within the deadline.
Extracted holding
The appeal could not be heard because the appellant neither paid the advance costs nor provided the required proof of timely payment.
Extracted reasoning
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.