Completing a bitcoin transaction I sent bitcoin to a company address for investment .  Transaction was confirmed. The output to the company address indicates that it has been spent.  However, the output to the other address shows output is unspent. Two questions: Does this mean the company has received the payment for the investment? Can l claim the unspent output ?
Does this mean the company has received the payment for the investment?


Yes

Once a transaction has more than about 6 confirmations it is regarded as complete and the money is fully under the control of the recipient


  Can l claim the unspent output ?


No and Yes.

If the recipient hadn't yet spent the money you sent them, it is still their money not yours. You no longer have any control over it.

The change returned to you is under your control, you can spend it whenever you want. Your wallet should show this change amount included in your wallet "balance"