I email them to have written conversation in case I need to and resort to the consumer protection authority, which is what is needed most of the time in order to extract refunds from low cost flight operators. Fortunately my most recent WizzAir tickets that needed refunding due to covid-19 flight cancellations were purchased through a ticketing agency, along with other Ryanair return tickets, so I filed my complaint against the agency. It took like 6 months and several e-mail exchanges with two to three week delays between responses to get a 90% refund.