R&B singer Brandy Norwood's mother filed a lawsuit Monday against Kim Kardashian accusing her of running up more than $120,000 in credit card charges without permission.

The suit, which also names Kardashian's siblings Khloe, Kourtney and Robert Jr., alleges they ran up the charges on the mother's card in 2006 and 2007. It seeks the return of the money plus 10 percent interest.

Kim Kardashian denied the allegations, telling PEOPLE she and her siblings had Norwood's permission to make the purchases.

"We have her signature on all items," Kardashian says.

In the lawsuit, Norwood's mother, Sonja Norwood, who is also her manager, alleges Kim Kardashian had only been authorized in 2004 to make one purchase on the Norwood American Express card in Kim's then-capacity as a stylist for Brandy (Brandy's brother, Ray J, also appeared in the infamous sex tape with Kim).

But later, Kardashian, now starring in the E! reality show, Keeping Up with the Kardashians, made unauthorized purchases and passed on Norwood's card number to her siblings, who also then made unauthorized purchases, including for items in two Kardashian family-owned clothing stores, Dash and Smooch, for a total of $120,636.