The Ubisoft UPlay Screwed me over

So I used the UPlay thing that Ubisoft gives you. And I went and collected all the feathers and got the Auditore cape and wore it in all the cities. Well…..i didn't get the achievement. So at first i thought that it was because I didn't wear it in Rome, But i went back and collected all the feathers on a second playthrough and still didn't get the achievement. So I think it has to do something with UPlay. So if you think it might be something else let me know.