Go to somewhere like Amazon and search for ADSL router.
If you log into the Vivaciti portal what does the connection status say, does it say it should be active or does it give a future date for activation.
When you spoke to BE you didn't mention the word cancellation did you? you should have just asked for your MAC and placed the order with Vivaciti using the MAC.
Only when you were safely connected with Vivaciti should you have told BE you wanted a final bill from them.
Virgin (ADSL) => Namesco => Newnet => O2 => Plusnet => Zen => Newnet => Zen => Freeola => Vivaciti (using O2 Wholesale DSL) => Xilo (C&W Wholesale) => Xilo (O2 Wholesale)
Router: Billion 7800N
Note: I don't lay turf for anyone. astro or otherwise, all views and opinions expressed are my own based on experience.