O2 are emailing my bills to a stranger!

Nightmare scenario been going on for months. The guy who sold me my package got one word in my email address wrong. I have recently sorted it out for the Virgin account but not for the O2 SIM card which forms part of the package. I have lost my SIM card and want a replacement. O2 apparently are unable to access my account but what’s worse is that the emails with my bank details a contract details are going astray. The email address they have on the system is definitely active. I am contemplating legal action because nobody seems to be able to help me. I have been in to the O2 shop and spent over an hour on the phone to customer service. It’s doing my head in!!!!