list of blocked email addresses

I am a long standing - and generally patient and tolerant  - TISCALI customer. (Now there was a company.) i have 2 interests which require me to use the net one of wnich has had to send my emails to a icloud address because they never reach me. Can i assume that  as i get every other email  - and many more for "cisco" etc - that it is blocked. And how do i get it unblocked please