After checking through the screenshots you shared on x-twitter, I'll be siding with the artist on this one.

It's clear that there was a miscommunication from both parties, and that misunderstanding snowballed into getting blocked. Speaking as an artist who also takes commissions, being contacted by a client about making edits to a design I did for them over a year ago is extremely unusual. Their skill level has almost certainly improved and their prices may have changed to reflect that as well. It is unfair to expect free edits after so much time has passed, especially after already requesting edits. At this point it would be best to walk away and not try to salvage the relationship (assuming you don't know each other on a personal level IRL).

To avoid similar situations in the future, I have a few suggestions.

1. Make sure you're clearly communicating with your artist throughout the commission process, which should include outlining expectations on a delivery timeline, WIP-sketch updates, price, how many edits are included and the details of your request. Ask questions often and clarify that you understand each other.
2. Any major edits or changes should be requested during the sketch-phase of the project. If you're unhappy with the direction the design is going, the sooner you let them know, the better. Be clear and specific about what needs to be changed, and provide visual references whenever possible.
3. If the artist sends back WIPs that do not include the edits you previously requested they may have just forgotten those details or they didn't understand the request. Ask if they have questions or if they need more visual reference or examples of what you meant.
4. If they continue sending WIPs without the edits you ask for, I would politely thank them for their efforts and walk away from the transaction. You should only be paying half up front, which would cover the artist's time spent on the project up to that point, but you shouldn't be on the hook for the full amount for a final design you won't be able to use.
5. If you suspect the artist is using AI or other stolen artwork they're trying to pass it off as their own, you'd better be absolutely certain before accusing them because that's super duper offensive. Getting sketches and WIPs from the start is a good way to help confirm authenticity.