No need to worry. Unless it is absolutely essential I never go into the
P.O. to post. Far too particular about testing the letter through the
cardboard slot. Always use the post box and you will be OK.
This has happened to me a number of times. Just keep plugging away and
if you are in the right you will win. It may take many, many weeks
though. Ps. Keep re-opening the same case number or you will get mixed
messages.
Sometimes I have had a listing fee charged when it was part of a free
listing promotion. I can take a couple of months to sort out but I if I
am in the right Ebay has always come to the party.