Rihanna's Trainer: Plenty of Pushups, Not Enough Payment

Songbird's former trainer sues, claiming more than $26,000 in unpaid services

Rihanna's slammin' bod didn't come cheap.

Not according to the personal trainer who's suing the songbird for more than $26,000 in unpaid services, anyway.

Cindy Percival filed a lawsuit last week in Los Angeles Superior Court stating that she was never paid for working solely for Rihanna in September and October 2009.

"She was made exclusively available to Rihanna," Percival's attorney, Scott Fischer, tells E! News. "She essentially stopped seeing her other clients and devoted her time to being available to Rihanna whenever she wanted to be trained. Some of that involved travel."

Percival worked with the Rated R singer for two years prior to those two wageless months and never had a problem getting paid, Percival says, adding that he doesn't know why his client had trouble all of a sudden.

Rihanna's camp has not yet commented on the suit.

"There's no explanation whatsoever," Fischer said. "Her management got a hold of Cindy and informed her there would be no further need for her services; but, in the meantime, Cindy had submitted invoices for payment and they weren't honoring the invoices. We sent the demand letter to them a month ago and they sent a response letter essentially ignoring the agreement."

"It's a shame that Rihanna won't honor her payments to her trainer," he added. The lawsuit's "in the process of service right now."