Hi Kian,
Sorry to hear that.
I have checked your account details and noticed that your Adobe Stock subscription has been cancelled and that is the reason the remaining assets got expired on 3rd of June, 2018 since you can use your available licenses as long as your subscription is active, but you forfeit any unused licenses upon cancellation of your subscription.
(After the cancellation of the subscription, the assets are valid until the last billing date, after which the licenses get forfeited).
Please see Common Questions about plans, purchasing, and availability, Adobe Stock for more information.
Feel free to update this thread in case of any additional questions.
Regards,
Twarita