Now there are massive blocking of Twitter accounts.
Most often, block accounts when you to use mass-following. Blocks is forever!
Also do not use hashtags #ICO #Cryptocurrency etc
Be careful!
UPD
Some accounts of my friends that have been blocked marked "forever" are now unlocked
But anyway, I think we need to be careful
He might also be following the Toceter socila media campaign and he sent it every day and over and over again.
We also have to give a pause in that matter so we can't say SPAM status.