All your data is perfectly safe with tool4seller.
We kindly recommend you not to use the "Delete Data" button on tool4seller if you decide to disconnect or cancel the authorization to tool4seller on Amazon seller central. Once you click the "Delete Data" button, the process is irrevocable. Even if you reconnect to tool4seller one more time, we only can fetch up the last 30-days data. The previous data of yours will be permanently deleted.
Please note that if you decide to delete data or disable authorization on tool4seller, you will no longer have access to sales analytics, inventory management, PPC optimization, keywords SEO and other features.