Her custody dispute with ex Kevin Federline has cost Britney Spears over $ 1million over the past five months and her conservators are concerned. They have filed documents challenging the billing and will appear in court Monday, March 11.

Britney has been charged $600,000 by Trope and Trope, her erstwhile law firm, and $500,000 by lawyer Mark Vincent Kaplan, who is representing K-Fed, reports TMZ.

Britney is required to pay K-Fed legal costs for the custody dispute, according to a previous court ruling.

The conservators are crying foul saying bills have been inflated. Trope & Trope, for example, often sent more than one lawyer to attend a hearing, which the conservators believe was unnecessary since it is a straightforward custody dispute.