entity framework 5 transaction doesn't commit - entity-framework

Question

I don't understand what is wrong with this transction
In case of error the rollback is ok
but the commit never happens
as the transaction was already interrupted...
What is wrong here?
Thanks!
try
{
using (TransactionScope scope = new TransactionScope())
{
//insert dati swap nella tabella PAPER_OPERATION
context.PAPER_OPERATION.Add(op_paper);
context.SaveChanges();
//si richiama la sp incaricata di effettuare un post processing sui dati dello swap
context.SP_PAPER_OPERATION_RUN(op_paper.ID_OPERAZIONE);
//per quanto riguarda la prezzatura la prima volta in cui lo swap viene inserito si tratta di un inserimento ex novo di righe nella tabella PRICING_PERIOD
//e a seguire nella tabella R_PAPER_OPERATION_PRICING_PERIOD
foreach (var pp_buy_to_insert in list_pp_buy)
{
context.PRICING_PERIOD.Add(pp_buy_to_insert);
context.SaveChanges();
R_PAPER_OPERATION_PRICING_PERIOD r_oppaper_pp_buy = new R_PAPER_OPERATION_PRICING_PERIOD();
r_oppaper_pp_buy.ID_PRICING_PERIOD = pp_buy_to_insert.ID_PRICING_PERIOD;
r_oppaper_pp_buy.ID_PREZZATURA_PAPER = Convert.ToString(op_paper.ID_OPERAZIONE) + 'B';
context.R_PAPER_OPERATION_PRICING_PERIOD.Add(r_oppaper_pp_buy);
context.SaveChanges();
}
id_inserted = op_paper.ID_OPERAZIONE;
scope.Complete();
}
var parameter = new
{
INSERTED_ID = id_inserted
};
return Json(parameter, JsonRequestBehavior.AllowGet);
}
catch (Exception e)
{
}