Can't to online tax return on time

I wanted to do my return on taxonweb, but I have locked my card.
I am abroad, and I can't get my PUK codes or go to the commune before Monday.

Is there something I can do before that?
(Would like to still be able to do my taxes online, and to avoid fines).

It is my first return in Belgium, and I have not received any tax-forms.