>>>Hi
1)Yes, customs duty is paid by shipping companies. About Bill of entry and about sample invoice you can watch module -8.
Link to BOE: https://www.amzblast.com/chapter/import-process-when-you-pay-through-wiretransfertt/
Link to Invoice: https://www.amzblast.com/chapter/mistake-in-performa-invoice-that-must-be-avoid/
2)You are paying GST two times. First when you buy product and second when you sell it. As per rules, your first GST should be returned when you file GST.
3)Customs duty is paid by shipping companies. No need to put on the invoice.
4)If you have activated DND(Do not Disturb) in your number then auto messages don’t come to your inbox.