If you are using Chargebee's hosted pages, you can set the address fields that are set as mandatory in the gateway to be mandatory in Chargebee. This should ensure that the customer enters the address information required from the gateway before moving forward during checkout.
Go to Settings > Configure Chargebee > Settings and Self Serve portal > Fields, choose the Address field under the Billing section and click on the edit option and render them as mandatory.
Refer to the screenshot below for reference:
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