Vodacom emailing problems

I have had the same Vodacom contract for over 15 years and have always received the statement, invoice and itemised billing statement by email every month. Now for the last four or five months I have not been receiving the itemised billing. So every month I phone the call centre and ask for it, so they send it then and there and say they will "activate" it for the future and then the next month the same thing happens. Why can't you get it right?