Toni Braxton's legal woes are stacking up - she has been hit with a lawsuit from bank bosses who allege she owes them money.

City National Bank (CNB) officials are suing the Unbreak My Heart singer for breach of contract, accusing her of failing to pay $900,000 she allegedly pledged in writing to pay back.

Bank bosses insists Braxton "made, executed and delivered to a CNB Promissory Note for $900,000" in November 2007, according to the lawsuit obtained by RadarOnline.com.

The star was due to pay back the amount by February 2008, but she renegotiated the arrangement after encountering financial difficulties.

Braxton then fell behind in payments in April, prompting lawyers for CNB to file the lawsuit, seeking $657,500 plus interest in excess of $44,000.

The 40-year-old was contersued by London insurance officials earlier this month after she launched legal action against them over the cancellation of a string of shows.