This time I was also returning a book to Amazon at the same time and I only later realised that I was given a »certificate of sending« for the book I was returning and not for the letter. I went back and received a hand-written “copy”. OK, thought nothing of it and forgot all about it …
.. until I received the letter back through my door saying:
There isn’t enough postage on this Airmail item so we are returning it to you. To resend it, please take it (with this label still in place) to a Post Office branch and pay the missing postage, or contact us on 08457 740 740.
Calmed down and called the Royal Mail, they told me I will have to resend the letter, but I am eligible for a £5 compensation. I just presumed the letter was not weighed correctly. If its under 20g it costs 56p, more if its over that weight. Instead of going to DHL (by the way the documents inside were relatively important) as I should have done, I went to the main Post Office in town and they said it is 56p as it is weighs only 15 grams!!!