What Can I Do If My Infant Is Constipated And Refusing Milk After Switching To Bebecac Stage 2, And Also Vomits When Given Solid Food?

Hi .. my baby is 8 month old but from 7 mobths i startd atage 2 formula milk dat is bebelac 2 .. but baby is constipated with stage 2 milk .... but when i wasss giving bebleac 1 befor 7 montha baby was ok and good but now with stage 2 milk babay is constipated and he is not intrested in milk ...so plz tell me what i can do And also my baby didnat eat solid food when i give him .. he vomits