Since i no longer use Citranet again for my ISP, my email account there was also not available anymore. I didn't reload the voucher and after one month, my account was deleted including my email account, so you will not be able to send an email message again to firstname.lastname@example.org. It's not available again. I tried to send a test email from my GMail account and here's what i got:
Sorry, no mailbox here by that name. vpopmail (#5.1.1)
This email was once my primary email since i used Citranet, but when GMail arrives, i switched to GMail since it has bigger quota and also free. Other important reason is ISP independence. When i'm using GMail, i could use any ISP to retrieve and send my emails, but if i use the email account from my ISP, i would have to use that ISP to send an email (well, i could find an open relay SMTP Server, but it's better to stick with the ISP).
Lately, this email account was filled with spams, so most of the time, i checked my account and delete the spams and if somebody has send me an email there, i would reply them and asked them to reply to my GMail account in the future. But since it's gone now, i don't think i can do that anymore.
I guess i have to make sure that this account is not used anymore on most of the services i used on the Internet or i will have problems in the future just because it couldn't find the email address.