Your Postgres data in the dependable-dedication project is still on its volume (roughly 136 MB), so nothing has been lost. Your trial has ended and the workspace currently has no active plan, which is why the service is offline. Subscribing to the Hobby plan ($5/month, includes $5 of usage) from your workspace billing page will bring the service back online and let you run pg_dump or continue using the database normally.

I understand I need to upgrade to retrieve my data, but I'm unable to make a payment right now. Is there any way you can provide a data export/dump of my database directly, or extend my trial temporarily so I can back up my data? The database is dependable-dedication / Postgres with approximately 136 MB of data.

We're not able to temporarily reactivate services or provide data exports on accounts without an active plan. Your data is safe on its volume and will remain there, but the path to access it is subscribing to a paid plan from your workspace billing page - once you do, the service comes back online and you can export freely.