предложу исправленно/дополненный вариант
Dear Sirs,
We thank you for the license being purchased.
We would like to pay your attention to the fact that, according to our agreement with ISP, we don't have any static IP addresses.
Moreover, our managers use your product where it is more suitable for them (at office, at clients etc.).
Therefore, any of our colleagues can use the licensed product, but from different IP addresses.
Please, refer the registration certificate of our organization in attachment.
Feel free to contact us in any cases,
Sincerely yours,
Mort1:Reanimator,
вы своим письмом благодарите компанию Azuon за то что они купили у вас лицензии?
ну и некоторые "выпавшие" буквы по тексту...
спасибо)