The official Olympic website does not mention any Swayamsevak medal for volunteers. Volunteers have not received any such medal.
The official Olympic website of the Tokyo 2020 Organising Committee issued three medals, gold, silver, and bronze, which have no resemblance to the photo of the medal circulating on social media. A list of all the products that would be delivered to the volunteers is also available on the website. It doesn't mention anything about a Swayamsevak medal for volunteers.
The website lists the items provided to volunteers for the Olympics. On working days, they receive some instruction, uniforms, and meals. They could travel throughout Tokyo's enormous railway system for up to 1,000 yen per day.
The Swayamsevak medal is a product sold on eBay, not a medal provided by the Tokyo Organising Committee of the Olympic and Paralympic Games.