A bit late, but this is why registering your domain yourself is the way to go rather than paying someone else to do it.
There's no need to leave it until the last minute to extend the registration, for example, and its bad if they did. I'd be livid.
In many cases, once the official renewal date is passed and it hasn't been renewed, it is not instantly made available for anyone to renew, but it may be more expensive to renew.
Its interesting that it's showing different expiry dates on different whois sites. Do you / whoever still show as the registrant?
It'd help if I knew the actual name in question, so if you can't post it here, can you pm me?