Flixbus Refused to Refund My Ticket After Force Majeure Cancellation

I purchased an international ticket on Flixbus, I needed to cancel this trip, due to force majour reasons(I sent my plane ticket via email to Flixbus as well) When I tried to change the travel hours, to book an earlier bus, Flixbus asked the cost of another ticket for a single journey, which is unbearable for me! I tried to reach an agent via phone but couldnot their chat system was awful so what I did is to purchase and return the ticket on the same day (a day before the journey) They refunded me 3.80$ as a voucher out of 22.98$, no money on my card. The rest of the payment, I was told is for cancellation fee! Even on cancellation policy, I should have got back 4.59$ as a refund. (on force majour reasons, most companies provided full refund) Please provide the rest of money either in voucher format or with a transaction to my credit card, otherwise I will make a formal compliant to show that Flixbus donot even follow its cancellation policies!