I have also shared some unpleasantness with them over "early" delcons, as in receive order on 8th, for delivery on 10th, sending shop "calls" and their sender has had a change of heart, and wants it delivered on the 9th, it gets delivered, it's "delconned" on the 9th, and the Merc Host sees that as a "late delcon" and doesn't "credit" your clearinghouse.
Have been extremely surprised at the high level of support at HQ these days, and am pretty pleased with some of the "new" support staff, so, this particular one, "suggested" that I set aside this order, and wait till the following day, to delcon..."I say, so,we are at a stalemate??.....YOUR system is UNABLE to be flexible, but, you want MY system to be flexible to YOURS??...I confirm AND delcon the day the order is delivered, would YOU want that function"??...yes, I'll be speaking to tech support and see how we can "solve this".....
By the way, she says, the "easiest way" to handle this would be to send a "date change" to the sending shop.....I give her ANOTHER order number, and after several ask/answers, the shop at the "other" end STILL doesn't get how to do it...we follow thru the paperwork, and her answer..."you'll be hearing back from me!!!"....