As of June 18th, 2013, the Endorse app has been closed. Per the notice on the app home page:
"You can withdraw your account balance and redeem points through 6 pm on June 30th, 2013. Thank you for using Endorse- we will miss having the opportunity to help you and your families. If you have any questions, please email us at email@example.com."
Be sure to cash out any rewards you may be eligible for before they are no longer available.