FlixBus - 13:30 hours delay because of border control

This Saturday (the 11th of april) me and 2 friends traveled from Belgrad (Serbia) to Budapest (Hungary). We arrived at 19:00 at the border of Serbia where we waited for a minimum of 15 hours (6 hours at the Serbian border, 9 hours at the Hungarian border) to eventually continue with the travel. There where a lot of busses waiting at the border which made it a long night. This forced us to spent the night and a bit of the morning in the bus, around 10:00 in the morning we passed the Hungarian border and could continue the travel. We booked a hotel in Budapest because the official arriving time from Flixbus said that we would arrive at 22:30 on saturday in Budapest, which was actually at 12:00 on sunday (a 13:30 hour delay!). At the end we couldn't even make use of the hotel and in addition had a terrible night in the bus. We were not offered the choice between reimbursement and continuation and we want to have a 50% refund of the flixbus ticket and a refund of the hotel booking.