Kirk Rothrum, who runs sound effects library Banging-beats.com, served Spears and bosses at Sony Music Entertainment with legal papers in May (15), claiming they used his work on her 2007 single without permission.

In the suit, he alleged staff at the record label lifted the sound of female moaning seductively for use on Piece of Me and he was never paid.

Rothrum initially sought a pay cheque for his contribution to the track, but he reportedly decided to pull the lawsuit due to the legal fees he was accruing as he chased a deal.

A source tells TMZ.com Rothrum was frustrated he was spending a lot of money on the lawsuit, which was ultimately going nowhere. He reportedly has been given the opportunity to refile the lawsuit.