In order to undelete claims that have been accidentally deleted navigate to the View my expense claims page. This is accessible from the side menu going to Expenses, MyClaims.
Once in the View my expense claims page, click the filter button.
Click on the Deleted button and then click on the claim number you wish to undelete.
Use the Save as draft button to reinstate the claim and return it back in your draft claims.
Clicking the Submit button will reinstate the claim and it will also submit the claim.