Simple delivery has many drawbacks, as combining say three items in one package only gives one tracking number , so two items never have proof of delivery and potential risk of buyer opening not received cases.
The only way to deal with buyer paying too much in fees is to make a partial refund of excess, but the situation above still exists.
The long winded solution is to with agreement of buyer, cancel all sales, then relist as one item, only one lot of postage and tracking number covers all items, and buyer buys again.
So much simpler before ebay invented a complicated system.
