The post office were really annoying with me last week.
I wanted to return a bridle I bought as it didn't fit so I wrapped it back up and took it to the PO... apparently it was too long to be sent via royal mail (so although lightweight and slim it was too big, I got asked if I could fold it and I said no, because it is leather and I'm returning it - I don't want it damaged) so they said it would have to be sent via ParcelForce for nearly £12. Phoned the company up (equestrian clearance) and they organised for it to be picked up for £7.50 and just took the money off my refund.
Then I had a heavyweight turnout rug that I had put up on eBay, I had boxed it up and that was 1cm too big to be sent royal mail so again had to go by parcel force but despite being much larger and heavier cost the same as the bridle to send (I had put £10 for p&p so lost a couple of £ but the rug sold for a good price so I'm not too fussed).
I don't know what they think they are doing tbh - it is really putting me off sending stuff via royal mail now