All the Smart Contracts you previously confirmed purchasing or subscribing to something, can be seen in the Contracts section. The latter is accessible from the bottom menu of the wallet. Depending on the Smart Contract status it’s in Active or Past tab.
If you hit the preview of the smart contract, you’ll be able to see more details, and the transaction history. For instance, if you’ve subscribed with monthly payments, all these completed payments will be reflected on the Smart Contract page:
The red icon in the top right corner stands for cancellation. If you want to cancel your subscription, just hit it and then confirm.