Q: How do I know my current call volume so I can predict cost?
You can see the volume (usage) when logged in My Account refer to Documentation : My Account > Tools - #5 View transactions and account balance
Q: Are the statistics by user, or is it all users?
A company with a business account is considered one user. Statistics as displayed in My Account represent queries for all phone numbers (employees) in the company. Usage reports can be generated by the Company's Admin (usually an IT person) - refer to Documentation : My Account > Tools > Usage
Q: What happens if a valid call gets blocked?
If it happen (because someone else reported a phone number and it is in the community complaints list) you just add that number into your White list and for your company (the user) this number will ring as a normal phone call as described in the Documentation : My Account > Tools > Whitelist - #2 Whitelist phone numbers so they will not be blocked
Q: If the lookup fails due to a service outage, does it allow the call to go through?
Yes. In case of outage or system overload etc. all calls go through as normal without blocking.