Blogs are the property of the users who register them, not the companies they may or may not represent. When we register a username account the blog with the matching name is reserved for our later use. There is no requirement that once registered any blog must be used.
Allegeing Trademark infringement and damage to a company perpetrated by the owners of an unused blogs is an interesting proposition.
Trademark infringement usually involves using someone's trademark on goods or service in a way that may confuse others about the source or affiliation of the goods or services. Intellectual property owners can report items that allegedly infringe on their rights just as copyright holders can. Generally speaking trademarked media can be used for Personal, Non-Commercial Use, provided appropriate attribution is used. If you think you have grounds for filing an abuse complaint here's the link > http://en.wordpress.com/abuse/