If Electric flux is independent of shape and we know electric flux = electric field multiplied by area vector so according to this electric flux of a sphere and a cube should be different as in case of sphere electric flux is equal to q/epsilon not where as in case of cube electric flux is equal to 3q/2pie episilon not.
Solution:-Yes your statement is correct that electric flux is independent of shape and size of object. It depends on charge inside the object. So electric flux through cube and sphere just depends on charge inside it , not on its shape obeying gauss law.