C.O.D. multiple items bug

I received multiple items in a single mail and paid the C.O.D. and took out one of the items. 3 days later the mail had expired and was sent back to sender (which was my own alt, so I saw this had happened. Then, in the sender’s mailbox, 3 days later the mail completely expired and was deleted.

First problem, if I paid the COD under what circumstances could it possibly be intended to send it back to the seller, who was already paid??? If it wasn’t my own alt, it would be just lost. Feels like a scam, really.

Second problem: GM response claims the mail system is not intended for storage. Well, of course I can see getting the rest of my items out in less than 30 days just like any other mail, but we get 2 days or so. The intention seems clear: that seller shouldn’t have to wait 30 days for the COD to be paid. The intention for all other mail is to have it cleared out in 30 days or less. These are different intentions. It cannot be your intention that sellers get the COD gold, AND the items returned. By definition: a bug.

If I had not seen this happen in my own alts, I probably would not have noticed. It would just be an unexplained drain of my resources. No telling the countless losses the players don’t even know they lost.