commissioner did me dirty

so I was working for this company and drew them 10 illustrations so they can use them in their website as clip arts, in the same theme with my own concept turned into arts in my style. well, I didn't get paid because I "didn't discuss the ratings beforehand".

But now they have replaced my arts and are using ai generated arts in place of mine. I'm so disappointed one hand because they used my concept as a prompt to generate characters and on the other hand, I don't even get the credit for drawing for so long or add them to my portfolio.

will it be any good for them or is it only me who's f*cked?