The Mercato wallet is designed to give you full and exclusive control over your private key. When you first download our wallet app, you are prompted to write down a seed phrase, that will help you recover your private key, in the case you lose it.
As long as you keep your seed phrase safe and do not install any malicious software on your phone, your private key will remain safe and in your control.
In the case you lose your seed phrase, we can still help. We offer a key recovery service, but you need to set it up during the signup process.