Spam is out of control

For months, I have been receiving an abundance of spam in my inbox. Every day, I will get between 20-40 new spam emails, some of them from the same source. I am constantly moving the emails to spam, but it doesn't seem to help. Why do items that I have marked as spam still enter my inbox? I have added hundreds of domains to a blacklist, but nothing seems to work. How can I get the spam to stop flowing into my Zoho inbox?