My baby refuses to drink his formula milk

Since birth Bona na milk nya then switch to Bonamil nung nag 6 months old sya. Nakaka 28-31oz sya a day noon pero ngayon nasa 17oz nalang naiinom nya sapilitan pa. What should I do? 😭 Nakakailang oz po ang baby nyo at the age 7months? #firstbaby #advicepls