Furidion Games have resolved an issue with the pricing of the Unbridled Fury rules on Wargame Vault.
From their announcement:
Unfortunately there have been some hiccups with the pricing of the Unbridled Fury PDF, which were outside anybody’s control. These should now have been fixed.
Please see our website for more details.
We apologise if any frustration or inconvenience has been caused, and thank you all for your patience.