Hey @intenscia, thanks for your help.
Well, I have no response of itch.io, so... I have the same issue :D how you can help me ?
Again, thank you!
I purchased on the 18th of December 2018, $18 USD which converted to £14.84 GBP (my local currancy), I'm aware that not exactly early in the project but I'm sure other people backed you a lot early for a similar price and it's close enough to the £14.99 full price. But then on release day you discount on Steam to £12.74.
I realise that you are discounting to gather sales and interest. But without this financial investment would you have got this far? Or so soon? I think indie developers forget that people paying for Early Access are taking 100% of the risk. If an EA game fails we don't get our money back, it's gone, the developer spent it.
It's also the case that we imagine that by buying direct from the developers that you get more of the profits as a 3rd party (like Steam) aren't taking any commission. By that token are giving you more support by coming direct.
Although we're happy to take this risk, it's a little insulting that even though backers took that risk on you, and in some case acted as unpaid Beta Testers, the people on the side lines get the rewards of a 15% discount. It's not a case of the money, I'm a well paid software developer and £2 isn't even a cup of coffee. It's the element of fairness and trust.
As a company you can't buy trust, you earn it. I, and anyone with an ounce of logic, will look at this and think "Why should I take this risk again?"
I totally agree orb505, I've figured out what happened. Itch.io sets prices in USD and then autoconverts to other currencies.
On steam we set the price for other currencies, and we did that not realizing there was a difference. The itch.io discount was meant to be the same, as itch.io was essentially a release for our fans ahead of the game shipping on Steam.
If you PM me your paypal details i'll gladly refund the difference or the full game (and you can keep the copy), as I can assure you we value our early access players, and due to the way these systems set local prices caused this slight discrepancy.
I noticed these instructions were shared by Rise of Industry previously. Let me know if these steps help:
Step 1 - Find or re-request the download page from your original Itch.io purchase email
If you haven't done so, find your original email with the purchase link.
Can't find your email? Go to this page: https://itch.io/docs/buying/already-bought and you can request that the download links be sent to you!
The page should look something like this, so click the "download page" link:
Step 2 - Click "Get Steam Key" and follow the instructions
Click the "Get Steam Key" button shown (check image). 
Follow the instructions to link your Steam account, verify your email if necessary and then copy the key to your clipboard.
Step 3 - Add your key to Steam
If you'd like, you can link your Steam key early, so on the 9th February all you have to do is install and run it.
Click on "Add a game..." on the bottom left of the Steam Library, then on "Activate":
Enter the key, as shown:
If everything goes well, you should get it confirmed:
Step 4 -
You can now download, install and play the game from your Steam library!
Troubleshooting
Q: I didn't create an itch.io account when I bought the game!
A: Go to the bottom of this page: https://itch.io/docs/buying/already-bought
Q: When I open the link to get my Steam key itch displays a 404 error.
A: This will happen if you open the link in a browser that is not logged in to your itch account. Ensure you're logged in to itch and try again
Once again, thank you for joining us on this wild ride!
https://discord.meeplestation.com Here is a discord link where you can speak with us!