Yes, this is a very poor way of handling the issue.
It's not like those 1 year vouchers have been stollen from them, they have been handing those out like candies and now they realized it wasn't profitable, they back off without any consideration for their customers.
It's been pointed out on Reddit that this move was not even legal in most EU because they have not been able to point out which of their ToC has been infringed (their official motive for cancellation).
I am tired of companies behaving like cowboys...