UnitedHealth expects to restore disrupted services for medical claims and payments platforms by mid-March, the company said late Thursday, as it grapples with the fallout of a hack that crippled its Change Healthcare tech unit late last month.

United's Change Healthcare unit is a vital lynchpin in the complex U.S. system for making and clearing insurance claims. The disruptions also impacted electronic pharmacy refills.

While its pharmacy operations returned online on Thursday, UnitedHealth said its payment platform will be operational on March 15, and its medical claims network will be restored on March 18.

Healthcare providers, including hospitals, submit health insurance claims to Change, which sends them to health insurance companies to evaluate and process.

After the cyberattack, these providers lost the primary means of processing payments for their services through patients' healthcare plans, forcing some to absorb the upfront costs.

The cyberattack on Feb. 21 at Change Healthcare was

perpetrated

by hackers who identified themselves as the "Blackcat" ransomware group, impacting players across the U.S. healthcare system.