Blacklisted email?

So I emailed a person who may or may not want to communicate with me anymore. It appears that the email was not received but rather ‘bounced back’ the message in the subject line said ‘blacklisted due to insufficeint funds’.. Is this some kind of message telling me I’ve been blocked or that this person’s work may not have money? I’ve never seen anything like it. PS it would not be referring to my money because this was a personal relationship never anything involving payment.