I have similar issue, but with a different flavor:

About 10 times per day I receive a blank email from an obviously throwaway spam account (e.g. vishal382190130 at gmail dot com)

For the life of me I cannot understand the purpose or goal of these emails, from the spammers' point of view. I've heard the theory that spammers will send "test" emails to check if a destination account is active... But every day? All the time? Is it possible somehow to assure the spammers that my account is active, and to start sending me actual spam, instead of empty messages?