RobJK ... when a rejection email is sent each moderator also receives a copy...so they too can keep up-to-speed on what is happening and/or where things have gone.
Unfortunately it is not all that uncommon that [for whatever reason] the intended recipient's email fails but we get the CCs anyway...and can [wrongly] assume the messages were sent successfully.
Apologies for that, but if you see something not succeed in being uploaded/accepted...and have received no notification just pop us an email, or a PM...and we can check it for you...
