public ResultMessage <IList <int> > GetFreeList()
 {
     try
     {
         var freeList = _rechargeService.GetFreeList();
         return(new ResultMessage <IList <int> >(freeList));
     }
     catch (Exception e)
     {
         return(new ResultMessage <IList <int> >(ResultCode.Fail, e.Message));
     }
 }