blocked from sending email

blocked from sending email

I have been blocked from sending email - with another 50+ to go this evening (UK time) - I have logged in as super administrator and the account does not say it is blocked, yet every time I try to send an email from the account this message comes up :
Reason:550 5.4.6 Mail rate exceeded limit
please rectify immediately.
your sincerely,
Stella Duffy
stella@funpalaces.co.uk