Mixed integer linear programming in matlab and cplex as solver

Hello, I wrote MILP code in MATLAB by making coefficient matrix using example cplexmilpex. It was tedious and time consuming, because one of my decision variables has 6 indexes (subscripts). Then, I call cplex to solve my problem which is fine but my objective value is zero all the time which I guess I might made some mistakes in my matrix multiplication... I was wondering is there any method/ example for MILP in Matlab and call cplex as solver which has decision variables with 6 subscripts, I meant more than 3 subscripts at least? Thank you! Samira