I also ordered a Nitecore 18650 cell charger a few months back. It cost about $26 but no duty was charged on it. It arrived in just 10 days. This custom duty thing depends on your luck. Sometimes big items get through without any duty. Other times little things get slapped with big duty. Even though customs duty is only 15% there are some additional charges such as sales tax fed etc. so in total you can expect to pay up to 35% to 40%.
You should have paid the duty and taken it. There is very little chance that it will be re-assessed in your favour. You might as well go back to your local postoffice, pay the duty and get the item. If you don't they will send it back to the main GPO. And when you go to the main GPO for re-asseement, you will be going from one customs officer to the next. It's not worth the time or the money and there is no guarantee the duty will be reduced.
And you can't even claim refund from Aliexpress, because if you refuse to pay duty it is your fault and not the sellers.
