During the 2020 COVID-19 pandemic (ongoing at the time of writing, 2020-05-06), many airlines are cancelling flights and then offering vouchers instead of refunds. Several questions address this issue already.
If I accept a voucher, I can no longer ask for a chargeback on the card used for booking, because the transaction will have completed. Now Condor Airlines write:
Allen Gästen mit einem geplanten Abflug von 12. März 2020 bis zum 28. Mai 2020 (Kurz- und Mittelstrecke) sowie bis zum 25. Juni 2020 werden persönlich kontaktiert und erhalten bei Flugannullierung automatisch ein Flugguthaben, das flexibel und vielfältig eingesetzt werden kann.
All guests with a planned departure between 12 March 2020 and 28 May 2020 (short and middle distance) and up to 25 June 2020 are personally contacted and in case of cancellation automatically receive a voucher, that can be used flexibly and in many ways.
That sounds like they're going to be issuing vouchers whether we want it or not. Condor are still legally obliged to give me a refund, but it may be hard to get one, so we may alternately try the card issuer. However, if Condor do give us a voucher without our consent (rather than offering it to us with the option for us to refuse), does that mean the route via our card issuer is closed to us?
(our departure date for an intercontinental flight is later than 25 June, but I assume the situation will not have normalised in July and that our flight will not happen)