@Simonas0 Were you trying to change your travel arrangements? Did your host cancel one of the bookings? It is strange, indeed because if you only booked once with one transaction there is no reason for something like that to happen at all because each credit /debit card transaction is assigned a unique ID number from the beginning.
If none of the above is true, contact Customer Service of Airbnb - it is a serious problem.
This booking seemed ok from beginning no cancellations or changes, so it is really strange, do you know how I could contact Customer Service of Airbnb? 🙂