If the DKV box is not working or Hungary has not been activated on the box, then alternatively you can buy a relational ticket with DKV fuel card. You can buy the ticket from web terminals at about 300 points of sales in Hungary, here’s the list: https://www.dkv-mobility.com/assets/documents/maut/maut_hu_overview_points_of_sale_pos_202012_de.pdf
When you buy the relatrion ticket frmo web terminal, you must enter intended route, vehicle type, emission class, number of axles and date. Choose DKV card as a payment method. Keep the ticket printout with you during the journey.
Twice a month