Still no itimized billing received via post

I took out a cellphone contract with Cell C. I made sure that they know to activate itimized billing and that they send it via post. I use the phone for work and my work only accepts the original statements otherwise they don't pay. I never received any statements via post, so called and was informed that I have not selected that option. Which is not true!!! I asked them to please send my statements and backdate from when I started the contract in April via post so that I am able to claim the money back from my work. It is now end of June and I have not received my itemized billing for May. The number for this line: ***. I have in the mean time cancelled the contract as Cell C cant provide service in my area anymore. But they still owe me this statement.