Billing should be able to add FiOS service to that account with no problem. It is common, though, for them to "accidentally" create a new account instead. If this happens, Tech Support should be able to do a process called a "scrub" - This takes your old account info and overwrites the new account with it, effectively giving you FiOS service with your old account. The only problem is that this process can take a long time, so it is faster to have Billing just add FiOS to the existing account instead of creating a new one to begin with.
Hope this helps!
I can arrange that scrub for you.. just send me a private message if/when needed.
Fiber Solution Center
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