Jan. 2 “marks 47 days since Genesis halted withdrawals,” Cameron Winklevoss, co-founder of the cryptocurrency exchange Gemini, pointed out in an open letter to Barry Silbert, CEO of the Digital Currency Group — which owns Genesis. Winklevoss went on to make a blunt appraisal of DCG’s business practices.

According to the letter Winklevoss posted on Twitter, Genesis owes Gemini $900 million for funds Gemini lent to it as part of the Gemini Earn program. “For the past six weeks, we have done everything we can to engage with you in a good faith and collaborative manner in order to reach a consensual resolution for you to pay back the $900 million that you owe,” Winklevoss wrote, adding:

“Every time we ask you for tangible engagement, you hide behind lawyers, investment bankers, and process.”

Winklevoss claimed DCG owes Genesis money that it has not repaid, leading to the failure of Genesis to pay Gemini.

Gemini was sued by investors on Dec. 27. The suit alleges that Gemini engaged in fraud and violations of securities laws because the Earn program was not registered and investors were unable to assess its risks fully. Earn stopped paying investors in November.

Silbert countered Winklevoss, claiming that Genesis has responded to Gemini’s proposal and that DCG is not overdue in its payments to Genesis.

“There you go again,” Winklevoss replied to Silbert. He went on to ask if Silbert would “commit to solving this” by Jan. 8.