Expecting art work for nothing

Just before Christmas I got an email from a PR agency asking if I would like to enter a promotional competition to have ago with a major UK toy company's 3D plastic 'pen'. It sounded good and the prize money was decent. So I agreed to enter, the PR company sent me the pens and I was off.

After a shaky start I managed to come up with the models below and as per instructions sent the PR agency photos and videos of my creations.

Despite being the agency's favourite I didn't win so that was that. Fair enough.

But the other week the agency got in touch asking if they could display my entries at the company's booth at the UK Toy Fair. There was no mention of payment or even paying for postage. I explained that they're welcome to them as they're just sitting in the shed but they'd have to pay for them. They graciously said I'd have my name on them but still no mention of sweet cash. After a few emails back and forth with me explaining that I spent quite a bit of time on them and this is my job and this is how much I'd like from them the communication from their end ceased.  I'm not surprised just disappointed. It's a shame that this seems to be the norm in the design world.
Here they are all heavily watermarked to hammer home my 'nothing for free' point for your viewing pleasure.