Hello again,
Forgot to ask these:

6. Where are youre servers located? in the US?
7. For the domains that we can host by your special plan (10 domains) can we have email accounts for each of them? Such as user1@domain1.com and user1@domain2.com?
8. Do you have any restrictions on email accounts disk space and attachment size?

Thanks again,
Ali

6. Where are youre servers located? in the US?

Our server are located in USA. Exactly, in Atalnta (GA), Dallas (TX) and Houston (TX).

7. For the domains that we can host by your special plan (10 domains) can we have email accounts for each of them? Such as user1@domain1.com and user1@domain2.com?

Yes you can have separate mail accounts for all your hosted domains.

8. Do you have any restrictions on email accounts disk space and attachment size?

Mail accounts disk space can't be larger that your total domain quota and you can modify it from your control panel. Max message size is 10M. but this value can differ in the different servers. If you need to set up a certain value open ticket please.