You do not have a 30 day visa, you have a 30 day visa exempt (most likely).
At most immigration offices, you will need to get your first 30 day extension of stay based on tourism. After you get a 30 day extension of stay based on tourism, then you can apply for a 60 day extension of stay based on unable to travel due to COVID-19.
Please see my post at
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For more information about the 60 day extension of stay based on unable to travel due to COVID-19