Entity type without key when execute procedure EF6

I’m new to Entity Framework, so I want to execute a procedure, but the class or entity without the data annotation Key, would that be possible? My stored procedure returns a single list of decimals, I read some examples and them used the SqlQuery<TEntity>(), but it causes an error that the key is not defined for this entity, can you help me please?

This is my example:

public class ReturnBill
{
    public decimal Discount { get; set; }
    public decimal Total { get; set; }
    public decimal IVA { get; set; }
    public decimal Extras { get; set; }
}

This is how I call the stored procedure with SqlQuery<TEntity>():

this.oContext.Database.SqlQuery<T>(SQLCommand, sqlParams.ToArray()).ToList();

this is my store procedure

create procedure QUERY.SP_GET_TOTAL_MONTHLY_BILL (
@vMonth int,
    @vYear int
)
AS
begin

IF OBJECT_ID(N'tempdb.QUERY.#TEMPBILL')IS NOT NULL
    BEGIN
     drop table QUERY.#TEMPBILL;
    END

SELECT  
    SUM(bDiscounts) as Discount,SUM(bTotal) as Total,SUM(bIVA) as IVA,SUM(bExtras) as Extras INTO QUERY.#TEMPBILL
FROM dbo.BILLS
WHERE bMonths = @vMonth and bYear = @vYear;

SELECT 
    *
FROM QUERY.#TEMPBILL;

end;

and this is the way that I try to get the procedure

enuConnection eConn = enuConnection.DBCounts;
      List<SqlParameter> pParam = new List<SqlParameter>(){
                         new SqlParameter("@vMonth",SqlDbType.Int,4){Value = 7},
                         new SqlParameter("@vYear",SqlDbType.Int,4){Value = inAnnio}}
                    };
        clsUnitOfWork<ReturnBill> oUnitOfWork = new clsUnitOfWork<ReturnBill>(eConexion);
          var oList = oUnitOfWork.RepositoryEntity.ExecuteOwnProcedure("QUERY.SP_GET_TOTAL_MONTHLY_BILL", pParam);

So the body of ExecuteOwnProcedure is:

public object ExecuteOwnProcedure(string sNameProcedure, List<SqlParameter> sqlParams)
            {
                string SQLCommands = "";
                int counter = 0;
                object oResult = null;

                try
                {
                    SQLCommands = sNameProcedure + " ";
                    Dictionary<string, object> oReturn = new Dictionary<string, object>();
                    foreach (var _param in sqlParams)
                    {
                        SQLCommands += _param.ParameterName;
                        counter++;

                        if (_param.Direction == System.Data.ParameterDirection.Output)
                        {
                            SQLCommands += " OUTPUT ";
                        }

                        if (counter < sqlParams.Count())
                        {
                            SQLCommands += ", ";
                        }
                    }

                    oResult = this.oContext.Database.SqlQuery<T>(SQLCommands, sqlParams.ToArray()).ToList();

                }
                catch (Exception e)
                {
                    thrown new Exception(e.Message);
                }

                return oResult;   
            }

Entity type without key when execute procedure EF6