Did you ask before posting the content that you are now asking for it to be removed? Before posting, you were specifically asked if the article is for promotional purposes. You selected No and then posted the article.
The editor has allotted you cash for the article and spent time editing it to make it look better. They might now ask for payment to remove the article. If you are fine with paying some amount for their effort, you can contact them at firstname.lastname@example.org for article removal.