Good idea, try this first to help determine the next course of actionIt looks like WA ha suspected any suspicious activity on your device and banned your device's IP address. You can try uninstalling the app and delete all your data related to WA. This might solve your problem. You can also try on another device using another network and get an authentic phone number for registration.
Any phone card can be registered, what kind of business are you trying to do?Where can I buy such an account?