It is, and since they're a B2B seller they are allowed to list the prices
excluding VAT:
"VoIP Services
Whether you are a home-based business or an enterprise customer, our wide
range of VoIP services allows you to unleash the power of the Internet to
transform your communications.
All rates provided are correct as of: Apr 07, 2021 | Connection charges
apply where indicated. | Calls are charged per second, with a minimum charge
of 1p. | All call tariff pricing is exclusive of VAT | Off peak rates apply
between 6pm and 8am UTC | Call rates DO NOT vary based on your geographical
location. | Call rates are subject to change without prior notice. Please
follow our Twitter feed for the latest changes. | Rates provided for
download are provided for information purposes only and VoIPtalk is not
liable for any inaccuracies or mismatch with billed calls. "
Theo