Our domain was abruptly blocked by our registrar this morning. Our NOC team and myself tried to get in touch with them and they tell us "Contact our legal". Even I could not get in touch with anyone beyond their phone operator. The domain was restored, but as DNS takes time to restore, we are still facing issues. They later claimed there were abuse complaints about Zoho.com emails (which is our personal email service with millions of free and paid users). We received a total of 3 complaints from them and two of them have been acted upon and one is under investigation.
Once we dig our way out of this, we will find ways make sure no one takes down our domain again this way.