The hooker, who plays for Cornish Pirates in the English Championship, started for the Fijians in their matches versus Australia, Georgia and Wales and came off the bench in their other pool game versus Uruguay at the finals in Japan.
It capped an incredible year so far for Matavesi, who also featured for Toulouse this year as a short-term medical cover signing towards the end of the Top 14 season.
However, the 27-year-old has now taken to social media in the hope that some treasured possessions collected in Japan can be returned to him.