You cannot delete a challan that is generated online. Please prepare a letter to your ESI regional office stating the reason and the challan number, requesting them to delete the challan. Scan the letter and send it to the EDP department of your ESI regional office. They will send a request to the Delhi office, and within a week, the challan will be deleted from your portal, allowing you to create a fresh one for the month.
Regards,
Kennady
Consultant - Labour Laws
Chennai