You can ask exemption under online data provision from yesterday

If there are no mobile signals in your area, you can submit an exemption request to NAV from 20 March. One solution is that you take the machine to a place with a mobile signal after the closing hour. If this is not possible, your application for exemption will be accepted and you have to send the datas via a media source into the system.

The communication can be downloaded from here: http://onlinekassza.hu/hirek/osszes-hir/536-tegnaptol-kerhet-mentesseget-az-online-adatszolgaltatas-alol