I seem to have fixed it. postfix was complaining about
Jan 31 15:52:48 h1870666 postfix/smtpd: warning: TLS library problem: 5738:error:02001002:system library:fopen:No such file or directory:bss_file.c:356:fopen('/etc/postfix/smtpd.cert','r'):
seems the smtpd.cert went missing, I mean it was a symlink but the target was missing. I pasted my certificate from startssl into it and that seemed to have solved it.
Also redid the steps of the tutorial that involved the ispserver.crt
Sorry for the ticket and solving it myself in a few minutes but I panicked.