If you cannot retrieve your Vega license prior to resetting your Vega, contact Sangoma technical Support to retain a copy. Submit a support ticket at support.sangoma.com with the Serial Number of your Vega.
How do I do this? Do I need to purchase FreePBX support credits? Some other kind of support contract?
You should have to login to https://support.sangoma.com/ and can create the support ticket under the vega gateways department. Having said that, you should have a valid support contract in place with that vega gateway serial number.