Do you have a webmailer?
Sure. The roundcube webmailer is accessible over https://webmail.tecserver.at
What is the master FTP user?
The master FTP user is the same as your Confixx user. These are connected - that means if you change the password for your confixx account, you also change the password for your master ftp account.
Where is the SMTP / POP3 / IMAP Server?
The email related servers are always direct accessible over your domain.
That means the SMTP server is on: smtp.[yourdomain]
The IMAP / POP3 server is on: mail.[yourdomain]
The login credentials for your email account can be found in the Confixx webmanagement panel