Bitcoin exchange MT. Gox has filed a counter-suit against its one-time partner CoinLab, demanding the return of around $5.3 million in customer funds.
Last November, Japan-based MT. Gox inked a deal with CoinLab, effectively outsourcing its operations in North America to its US counterpart.
However, within months the relationship turned ugly and CoinLab filed a breach-of-contract suit against its partner, demanding $75 million, claiming that it has "wilfully failed to perform its obligations".
MT. Gox has now hit back with a counter-suit arguing that the breakdown of the partnership is CoinLab's fault because it failed to register with regulator FinCEN as a money transmitter.
MT. Gox also says that of the $12.8 million its customers deposited in CoinLab bank accounts, $5.3 million has yet to be returned.
Earlier this year the Japanese exchange had around $5 million in customer funds held in accounts with Dwolla and Wells Fargo seized by the US Department of Homeland Security.