Yandex · ya
Yandex uses code ya. The directory also has distinct entries for yandex.taxi (yti) and YandexGo (wf). Match the service requested by your task rather than assuming one Yandex-related code covers the whole family of products.
Connected countries and reward conditions can differ between these entries. Choose the exact one before requesting a number. The public page does not change account permissions or guarantee that a number will be accepted by a different Yandex product.
SMScash is an independent platform. A temporary number is not permanent ownership, and acceptance by a third-party service is not guaranteed. Follow that service’s rules.