Cisco has sued Acacia to keep its $2.6 billion acquisition deal alive after Acacia tried to back out.

Cisco announced in July 2019 that it was purchasing Acacia for $2.6 billion. Acacia makes optical components that would aid Cisco in its efforts to gain a meaningful share of the 5G network market. Since the announcement, the two companies have been working through the regulatory hurdles necessary for the acquisition to proceed. Acacia, however, is using one of those regulatory hurdles as a reason to try to back out.

According to a company statement, Acacia is terminating the merger agreement because it did not receive approval from a Chinese agency in time.

Because approval of the Chinese government’s State Administration for Market Regulation was not received within the timeframe contemplated by the merger agreement, Acacia did not have an obligation to close the merger before the arrival of the January 8, 2021 extended end date. As such, Acacia exercised its right to terminate the proposed transaction in accordance with the terms of the merger agreement.

Cisco has challenged Acacia’s stand, claiming that all conditions have been met, including approval from China’s regulator. Cisco applied for a court mandate prohibiting any termination of the merger agreement until a court could weigh in. Cisco was granted the order on Friday.

At this point, it remains to be seen how the merger will play out, but it appears any resolution may not be as amicable as hoped.