If you have received show cause notice from customs for importing adult toy then it becomes your duty to either give them a reply or visit their office on the date prescribed in the notice to attend the inquiry.
Please note that the buying of adult toys online or importing it is prohibited in law, hence the customs will seize the product and may issue notice seeking your explanation that why action should not be taken against you for this criminal offence.
You can even issue a reply notice claiming innocence of the law involved in this and to apologize you for this omission and also you may authorise them to confiscate the item and request to waive your personal appearance before them.
If you are not able to give a proper legally valid reply notice then you may contact any lawyer and proceed on his/her instructions to tackle this issue.