I went thru something like this a few months ago, so here is my
First, you dont "own" the domain name, you are leasing it on an annual basis.
Second, just because you have the domain, does not mean that you automatically own the "name", such as sex.com to sex
Third, just because you own the company name does not allow you to copywrite and take the domain name if it belongs to someone else. Such as if you have start the company "Larry's Applicances" tomorrow, but someone has the domain registered prior to that, its a tough fight. However, if you have the copy write or trademark on the "name" and some reg's a domain after that point, then you can get it back based upon some trademark/copywrite issues concering your name.
Again, im not 100% on this, but was in a similar situation a few months when someone tried to say that i was infringing on copy write because of a domain name i had which had their name in it.