Unable to send message;Reason:550 5.4.6 Mail rate exceeded limit

Unable to send message;Reason:550 5.4.6 Mail rate exceeded limit

I don't understand why I am being blocked.  I sent 28 messages yesterday and maybe 6 today-all sent to a single address.  How is that mass mailing?  To have such a small limit on sending emails is kind of crazy!

How long until I get my account unblocked and what is the actual number of emails I can send from here?  I could not find anything specific as far as time and amount of emails.  If I have no idea how many I can send, how can I use Zoho?  I never heard of such a thing for such a small amount of emails!