Handoff does not currently have a way for users to recover or "un-delete" deleted estimates and projects. This is a feature we're working to build within the next quarter. In the meantime, please message our Support team and we can assist with the recovery.
You can contact support in Handoff by clicking the Settings icon (the gear icon), scroll down, click "Contact Support". This will open a chat with a support agent.
Please provide as much identifying info as you can about the deleted estimate/project so we can locate it. Helpful info includes any of the following:
estimate/project name
estimate/project number
client's name
total price
date you last accessed it.