Kim, along with her siblings Khloe and Kourtney, lent their name to the Kardashian Prepaid MasterCard, which lets parents give their children a small amount of credit so they can keep track of their finances.
The scheme costs every user $7.95 (£5.30) a month to run and also includes a $1 (66 pence) fee to add money to the card as well as $2 (£1.30) per transaction to pay the bill automatically.
The attorney general of Connecticut launched a scathing attack on the siblings earlier this month (Nov10) for promoting the card, accusing the stars of peddling a ""dangerous financial fantasy"".
Lawyers for the stars' corporation, Dash Dolls, LLC, have now issued a ""notice of termination"" to the companies behind the card and ended the endorsement deal, according to GossipCop.com.
The legal letter, sent on Monday afternoon (29Nov10), states the Kardashians ""have worked extremely long and hard to create a positive public persona"", and are recognised as ""honest, ethical, and fun-loving individuals who are kind and caring to others.""
According to the document, they've decided to terminate ""the agreement in its entirety, effective immediately"" because the card ""might violate"" certain laws.