add experiences with t-online.de blocklist delisting

service/email.md

@@ -524,6 +524,10 @@ Let's try to collect our experiences per provider here:
 You can request delisting here: https://olcsupport.office.com/ , you need a microsoft account to do so.
 They should get back to you soon to resolve the situation, if needed you can contact them on outlooksupport@microsoftsupport.com
 
+### T-online.de
+
+You can mail tobr@rx.t-online.de to request delisting, they usually respond pretty fast.
+
 ## Disaster recovery
 
 N/A. The server should be rebuildable from scratch using the Puppet