The Federal Trade Commission is demanding that Amazon's founder and executive chairman Jeff Bezos and CEO Andy Jassy testify before the agency as part of its expanding investigation into the company's Prime membership program and other services.

The FTC is investigating whether Amazon misled customers to gain and retain subscriptions. The agency on Wednesday set an Oct. 7 deadline for the pair to testify.

Amazon has maintained that its signup and cancellation processes are "simple and transparent and clearly present customers with choices and the implications of those choices."

In August, the company accused the FTC of harassing its officials and requested the agency to end its inquiry. The FTC said it considers the two Amazon executives to be key witnesses.

The company called for a halt to the inquiry, or for a delay of the executives' testimonies.

The FTC's demand for the executives' testimonies added the company's growing legal troubles. The FTC has also started an investigation into Amazon's $1.7 billion acquisition of iRobot.

The United Kingdom's media watchdog also launched an investigation into the control Amazon, Google, and Microsoft have on the cloud computing industry. Amazon previously faced anti-trust scrutiny in the U.K. earlier this year. Last week, California's attorney general sued the retail giant alleging unfair pricing.