Microsoft is suing Samsung for $6.9m (£4.33m) in unpaid interest, an unsealed lawsuit has revealed.
In August Microsoft announced it was suing the South Korean firm in a dispute over unpaid interest on Android patent royalties.
The lawsuit, now made public by a New York federal court, reveals that although Microsoft has already received a massive $1bn in royalty payments, Samsung has stopped paying up in an alleged protest against the software giant's takeover of Nokia handset unit.
Samsung agreed to pay the $1bn of royalties as the Android operating system, utilised by the firm for its successful smartphone products such as the Galaxy Note 4, uses Microsoft technology.
However, according to the lawsuit, Samsung initially refused to make a payment following the Nokia deal, before doing so but with interest withheld.
After filing legal action in August, Microsoft Deputy General Counsel David Howard said:
In September 2013, after Microsoft announced it was acquiring the Nokia Devices and Services business, Samsung began using the acquisition as an excuse to breach its contract.Microsoft and Samsung have a long history of collaboration. Microsoft values and respects our partnership with Samsung and expects it continue.