Unfortunately many companies are playing this dirty game. I have a voucher from Iberia. When my flight got cancelled I rang up and I was told that my only 2 options are a voucher or rebook. The website says that they do offer refunds... Also it looks like that LH group does not offer any refunds, at least Lufthansa and Swiss. Some countries have passed laws that a voucher is fine instead of a refund. Some companies are ignoring EU law and a very few small percentage of companies are actually offering a proper refund.