[Poseidon]

Have you already payed the company?

1) If yes:
Ask for the website "as it is" and ask for a refund of some of the money, giving them a reason, saying its taken x amount of months and its not complete.
2) If no:
Ask for the website as it is and negotiate a new price to compensate you for them not completing the site. If this is refused. Tell them - "you broke your half of the contract, now im terminating the deal, i'll go elsewhere."