Are My Infant Twins Frequent Watery, Seedy Stools Due To Lactose Intolerance Despite Switching To Nan Lo Lac?

Hlo doctor I have twins and 90 percent on formula feed they were born at 36 weeks 6 days from first I have given dexolac special care now they are 2 months 20 days old from past 10 days Dey are having loose watery seeds like motion den I went to doctor and used medicine bascillus,taxim o drops i even changed to dexolac 1 still the same den i again consulted the doctor he told me they are gaining weight it is due to may be lactose intolerance use Nan lo lac today I have given lo lac but still she is pooping the same what should I do how to ease my babies am giving 60 ml with 2 hrs gap .. please help me