You can follow the letter to GST officer format to respond to the notice from the department  to avoid any complications. Letter to GST department has to be precise and must have the clarification in context of the notice .it must include answers to all the question that have been posed by the department.

If can be issued by the GST authorities under the following circumstances under document identification number , without containing the DIN any show cause notice or letter is invalid , the person need not answer to such show cause notice or letter and they may be treated as non-est in the eye of GST law.