Natura Viva's booking application in Finland charged double the price after making a one-day reservation at the accommodation. The receipt I received didn't really show that there was a mistake, but I assumed that the price for the Friday-Saturday reservation was double. I couldn't find the price list for the reservation or the price breakdown on any site, so it was difficult to determine what the issue was. I sent an inquiring e-mail to Natura Viva's customer service and after the weekend Natura Viva promised to refund the extra price they charged.
I assumed they would provide additional compensation due to the system error I found. Yet, they did not offer any additional compensation and, despite my request, they did not agree to pay. If I hadn't noticed the double charge myself, Natura Viva wouldn't have noticed it either, and I would have paid the price of two days for a one-day reservation, i.e. €149 too much.
I hope no one else has had to pay double the price for booking Natura Viva. A warning about possible double charging should also be visible to the booker. Now apparently the system error is being fixed, so it may be that this error will no longer occur. However, I urge Natura Viva customers to check the charges for their own previous bookings, if it is still possible.
However, Natura Viva did not praise me in any way for finding a system error and reporting it, which raised my doubts about Natura Viva as a reliable operator and a party benefiting from double billing.