Poriya Hossein Khanzadeh and Ali Hajipour scored 22 points each, while Bagunas led the Philippines with 22 points.
Iran started the campaign with a 3-1 loss against Egypt and defeated Tunisia 3-1 in its second match.
Team Melli booked its place in next stage as the second team.
Italy is the defending champion, having won its fourth title in 2022.
Taking place in Manila, Philippines, the championship features 32 teams from across the world competing for the coveted title, divided into eight pools of four teams, where the top two advance to the knockout stage.