Hi there, sorry to hear you have not been able to access this content after purchasing it on the PSN store. While I would generally advise contacting the Sony / PSN team directly to check for any potential errors with how the license you have purchased shows on your account or anything on their system preventing the download of this content, we may be able to shed some light on the subject and assist in being able to get this content downloaded.
First of all, would you be able contact us directly via our social media accounts on Twitter or Facebook with your Ubisoft username and the PSN gamertag you are attempting to access this content on along with an image of the back of the game box if this was a physical disc purchase and not a digital download. Alternately, you can contact our support teams directly with the same information by creating a support ticket here.
If you have any further questions or are having any difficulty contacting us using one of the above methods, please feel free to let us know and we will attempt to assist further.