@LAKSHMANSHANKAR C We understand that you are concerned about charges for a deleted web app.
Please note that you need to this link, which will list all of your resources. Please review this list to ensure all resources you want are deleted so that no further billing is encoutnered.
If you are still concerned about charges, please navigate to this site(click "submit a support ticket", where you can open a free support ticket to receive assistance on billing and subscription matters.