American retailer Walmart Inc. has ended its contract with Bossa Nova Robotics as it shifts back to human workers.

Walmart is ending its use of the company's robots which it had used to help stock shelves at some stores.

A report from The Wall Street Journal says Walmart had conducted several tests and research on the cost-effectiveness of using humans versus automated robots. It found that hiring people yielded the same results and costs.

Sources familiar with the matter said in the report that Walmart had chosen to cut its ties with Bossa Nova Robotics after it had concluded its research. Walmart reportedly said that there were about 500 robots working at around 4,700 of its stores.

The need to properly stock its shelves grew during the height of the pandemic as consumers bought up essentials such as toilet paper and canned goods. The company had to make sure there were no shortages at its thousands of locations nationwide.

The problem grew as the company's online sales nearly doubled during the second quarter - challenging its current stock systems. In a recent interview, Walmart CEO Doug McMillion said making sure its stocks were adequate had become a big problem.

Sources within the company said Walmart decided human workers were best suited to manage products on its shelves. They proved to be equal to and sometimes slightly better than robots.  Walmart U.S. chief executive John Furner was concerned over consumer reactions to robots in its stores, the sources claimed.

This doesn't necessarily mean the end of Walmart's use of advanced technologies. The company is reportedly launching other tech-based experiments in some stores.

Last week, the company opened four new stores that it turned into "e-commerce laboratories." Within the stores, the company plans to test out different digital tools and equipment to enhance its restocking and fulfillment systems.