I paid with debit card.
The point is that they cancelled the route, and they offered the option of refund or change. I chose the refund because I don't trust in that company anymore and thought was better not to have another ticket in risk of cancellation. I bought my flight in february to travel in June, because it was the cheapest I found and I had a reduced budget.
Since the company isn't bankrupt yet (to my knowledge), I pretend them to give me the money back. They offered that option and must follow that I think.