A valid US business address is required to open and run a business in the United States.
That being said, if you've canceled Firstbase Mailroom™, then you need to make sure you have a mailing address in the US. Follow the next steps to be in compliance with the IRS and the mailing operator:
Notify the IRS about the business address change using the following form: Form 8822b.
Get in touch with the mailing operator of the state you’ve chosen when signing in for Mailroom by contacting them in the first 24hrs which is enough time to receive notifications and retrieve any piece of mailing.
Call the IRS for any updates on this change.
In order to learn more about changes in the business address, please check the following support article. Please notice you can re-activate Mailroom at any time, further information can be found here.