trouble updating billing address

Hi, 

I am really frustrated with this issue, I’ve been trying to update my billing address for two months now and the customer service team keeps getting it wrong! I have a mobile line and an internet service as well and in the detail charges section ( page 5 of the bill ) its showing wrong addresses for both devices its driving me crazy. I was reassured probably 15 times that my address had been successfully updated and then comes the bill and surprise…. Nothing changed. I am desperate since I need the addresses to match so I can open my bank account, they ask for a utility bill and this is the only one I can provide please help!!!