Was that a form by Microsoft? Would be great if you could share that, I’ve been looking for something like this forever!
It's the first link in the delisting section: http://go.microsoft.com/fwlink/?LinkID=614866&clcid
I also recommend signing up for SNDS.
https://support.microsoft.com/en-us/getsupport?oaspworkflow=...
Check your /24 neighborhood first though, one of your neighbors might be sending spam: