Great, one thing i suggest is to split the confirmation to 3 phases if not done this way:Mane wrotetransfers the money to the traveler only once we get a confirmation that the goods have been delivered.
1- Item is purchased, share the invoice.
2- Item/traveler arrived to the buyer home land, send a notification that the item is ready to be delivered upon an approved location to meet.
2.a- if the buyer didn't respond within 3-5 days of arrival, the traveler have the right to get the money and the item.
3- When delivering the item, the buyer should click on some button within the app/website to confirm the delivery is done which requires him to have internet connection, ounce done he cant remove his confirmation and he can let the traveler see the confirmation from his device if he doesnt have an internet connection.
I'm sorry if the confirmation is already done in a better way and already published in your website as im interested to read it.