Edit: Horubrain is fixing it. If you bought the full version before Deluxe was a thing contact them on Discord.
Just gonna leave this here for the dev.
https://itch.io/docs/creators/quality-guidelines#do-not-upload-misleading-conten...
Note that it says "Statements about included content that doesn’t exist". If you sell something called the full version of the game and then lock the people who purchased it out of the full scale of content then you are flagrantly making a misleading statement about the content of what is being sold. Changing the name of that version to no longer be called the full version AFTER the fact does not change that your customers purchased it under the premise of it being the full version.
I really like what you're making here and I contributed money because I had faith that you were going to make it even more interesting, but you're spitting in the faces of your customers on what appears to be your first ever project by essentially taking away what you sold them. You still have a chance to fix this, and I really hope you do because I like what you're making. This appears to be your first ever project, and how you resolve this situation is going to shape how people view you in the future and whether or not they trust you to make quality games. You do NOT want the first impression you leave with the gaming community to be that you're dishonest and untrustworthy because that's going to shape everything about how people view and engage with you as a developer.
For your own sake and because I want to see what you do in the future I hope you can see the sense in this. I'm not asking you to make the Deluxe version the same price as the standard version or to reduce the price. I'm asking you to treat it as the full version and make sure the people who paid for the full version early on are able to receive what you implicitly promised them by calling the version you sold them the full version.
There are several ways for you to rectify the mistake you've made, and the earlier you do it the better it will look for you in the future. And for the love of God, please don't make the mistake of trying to cover up your screw up instead of making it right. That will absolutely destroy any positive image people have of you in the future.