The expiry process for Plus accounts hasn't worked since we moved servers (I thought it was a bit quiet on the expiry notice front!) which means that when it does finally run this week (assuming I have now correctly fixed it!) that some people will get expired and will only get the 'You have expired' (of course not them personally having expired - their account!) email, without first getting the 'You will expire in one week' email first...
Sorry about that!
Steve