You will learn more about the Russian-women- dating-world in common.
Being prepared is being halfway your success in finding you Russian lady.
These persons mostly don't answer your specific questions and don't give much personal information, but use general (predefined) text for their letters.
This is at least a sign that you have to be careful.
Do not use any free dating site where women can contact you first. Any person can signup here complete anonymous (use any free email address and fake personal information).
Even when you have to pay to be a member (for receiving emails) on these free dating sites, don't use it if you are serious in looking for a new life partner.
Another important thing is to confirm with her if your (original) letters indeed are reaching her.
But if this and all our other information is not enough for you to feel yourself 'well prepared' and certain then you always can decide to provide yourself with more information, tools or services.
It's you who has to make the choices, but making the wrong choice can cost you a lot of money.
Try to send copies of your original letters using postal mail or a fax machine at her office (if possible) and ask her if these letters are the same she received through the Dating Agency you are using.
I know examples that some Dating Agencies, with this kind of services, can create additional questions or add more text to your letters or even change your letters, just for the reason to keep you as long as possible as their customer.