If you haven't done so, ask the client politely to close the contract. I wouldn't ask more than once though. Then, if they still do so in a week or so, close it yourself. Some clients will never close the contract.
You may request your client to end the contract and submit feedback. It is always best to have the client end the contract to ensure that you receive feedback since this is a required step when ending a contract; however, if the client is unresponsive, you have the option to end it. This will send a notification to the client requesting them to share their feedback for you.