Even worst I just found out that 1. requesting a pop3 email box will be refused 2. smtp access is closed/blocked

Not good if you want to use OTRS at all.

IMAP is said to be working thought! I dont understand how IMAP can be working if SMTP is closed

IMAP is for fetching mail, SMTP is for sending.

And I was told something very weird in the lines of that some ppl use pop3 to send emails, does this even make sense!

No it doesn't. POP3 is only for fetching mail. Anybody tell you otherwise, that's the drugs talking. -- Lars