First order was paid on site using Paypal.
Customer sent an email to ask to add something more, which he did.
Sorry but it seems not possible.
When it's paid on site, the order status is then "Paid" and buyer
CANNOT add to it.
Any new order will make a different one.
I'm lost
Second order (second batch) wasn't paid yet.
Afterwards, the customer asked us to remove the second batch again.
Now we're stuck on how to proceed, since we cannot remove the second batch
without cancelling the entire order.
You could (but it'll cost you the fees):
* refund the payment
* set the order payment status to "Not paid"
* then make an Item Removal Request for the items buyer doesn't want, approve
them
* then reinvoice and let buyer pay again
But see above there's a problem in your process, one cannot add after an
on site payment.
Someone did something abnormal?