The 'In Da Club' hitmaker, who is now the face of Sms headphones, said he partnered with executives at Sleek Audio Llc in 2010 and offered up cash that he was supposed to get back, reported Contactmusic.
In his new suit, the 27-year-old rapper said his former partners still owe him 178,000 pounds.
But his former partners claim the loan was nullified once 50 Cent teamed up with a rival and created the Sms line.
They alleged that he "purposely omitted and misstated information during their negotiations with intent of fraud", insisting they would never have borrowed the money if they had known that he would not see the deal through.
However, the rapper's lawyers claim they have attempted to settle the matter and recoup the money and now they are planning to go to court to ask the company to return the advance money, plus interest - and pay their client's legal fees.