Though not a serious issue, don’t ignore it. Legal matters (especially with the government) might/might not come to bite you.
I too had imported a sex toy and the same thing happened to me. Got a notice from customs.
I wrote back that I ordered it accidentally and since I am a law abiding citizen, I agree to pay the penalty. I sent a cheque for the same as per the instructions received in the letter.
The max penalty they will charge is โน5,000/- or the value of the imported product. Whatever is higher.
If ignored you might get a show cause. Not scaring you but it’s better to just pay the penalty and not leave any loose ends.
I received an acknowledgement and the case was closed after payment of the penalty.