Oh god, the sale is international, things just got 10 times worse.

It is highly likely you are being scammed, especially as the buyer wants you to falsify the customs declaration,

Check customs, for the penalties for doing so.

What are you going to do, when  the buyer claims you have not sent the item they purchased, but instead something valued at $180.

New seller - high value item  -  I would expect your funds to be held for 30 days, possibly longer due to international delivery.