eBay Inc. (EBAY) - Get Report wants Amazon.com Inc. (AMZN) - Get Report to stop illegally poaching sellers for its marketplace through eBay's own messaging system, according to The Wall Street Journal, which viewed a cease-and-desist letter from the company. 

EBay sent the letter on Monday, Oct. 1, alleging that Amazon has about 50 sales representatives worldwide that sent more than 1,000 messages to sellers on its platform. EBay began investigating the matter after it was alerted by a seller. 

The cease-and-desist letter claimed that Amazon was violating California's Comprehensive Computer Data Access and Fraud Act as well as the company's own user agreement. 

"We are conducting a thorough investigation of these allegations," an Amazon spokesperson told TheStreet.

Amazon is a holding in Jim Cramer's Action Alerts PLUS member club. Want to be alerted before Jim Cramer buys or sells AMZN? Learn more now.

Want to Buy $1 Worth of Stock for 90 Cents or Less? You can with certain so-called "closed-end" mutual funds - an often overlooked investment class. Click here to register for a free online video in which TheStreet's retirement expert Robert Powell and an all-star panel tell you all you need to know. The webinar is sponsored by Nuveen.