The subscription to Anstrex Dropship platform is store based. You need to detach each connected store from Anstrex to cancel the subscription.
Follow this tutorial to unsubscribe or cancel a Shopify store.
Follow this video tutorial to unsubscribe or cancel a Woo-Commerce store.
Please note that you will lose all the products/orders/alerts-history etc. on Anstrex platform permanently, when you cancel your subscription and detach your store.