Key legal question
Whether the appeal could proceed despite non-payment of the required cost advance within the grace period.
Extracted holding
No. Because the appellant did not pay the advance or provide proof of timely payment, the court had to refuse to enter into the appeal.
Extracted reasoning
After a warning under Art. 62(3) BGG, non-payment within the non-extendable grace period triggers non-entry under Art. 108(1)(a) BGG.