Also would like to know. My use case requires return labels for every
shipment. Luckily 98% always get used, but there's always the few that
do not get used, and I'd rather not have to chase that down all the time
to cancel.
Did this ever happen? I am strongly considering moving my business to
shipstation, but this is a showstopper for our workflow--need to link
directly from our CRM based on the ID that comes in via api.