AceShowbiz -

Rihanna served her ex-accountants with a lawsuit, accusing them of doing a poor bookkeeping while they were working for her. As results of their mismanaging, she suffered "significant net losses" and dealt with an ongoing IRS audit of her tax returns between 2008 and 2010.

Riri claimed Berdon LLP and its former employees Michael Mitnick and Peter Gounis failed to inform her and give recommendations to trim expenses when her 2009 "Last Girl on Earth" tour was losing money. She also alleged the accountancy firm took more than they should have in commissions.

In the lawsuit, the "We Found Love" hitmaker stated Berdon cost her tens of millions of dollars from touring revenues due to an unusual method of sharing profits. The firm reportedly grabbed 22 percent of the revenue, while the 24-year-old chart-topping singer herself only got 6 percent.

"Despite having earned millions of dollars in revenues during Berdon's tenure Fenty learned that her net income after payment of expenses and exorbitant commissiones to defendant was a fraction of that amount," Riri complained. She's seeking unspecified damages for breach of contract, misconduct and negligence

Riri, whose real name is Robyn Fenty, hired the firm and its accountants when she was just an aspiring 16-year-old singer from Barbados. She fired them in September 2010, and her fortune has been reversed ever since. According to the legal papers, she managed to pocket 40 percent profit from her "Loud" total revenues.