Invoices not received each month, for 2 years!

I do not receive my bills for one of my contract numbers every single month. I receive my bill for the one number (via email), but never for the other. Every month I call in and ask them to correct it, and they say that they have, but the next month comes and I still do not receive my bill. This has been going on FOR THE ENTIRE DURATION OF MY CONTRACT, THUS FAR!! Even before renewing my contract I had the same issue. It has been 2 years!!!

How difficult could it possibly be to update an email address on an account!!!!??? This is frankly ridiculous! I have had so many phone calls with them and it still is not fixed. Poor poor service.