Thank you for posting, @Tranquil_solution6a04.
Thanks for sharing your experience, and thank you for being an Adobe customer. I can understand your frustration if Firefly is not delivering the results you expected and you feel the service is not providing the value you paid for.
I also want to acknowledge the troubleshooting suggestions provided by @Oh.N8. The questions and testing steps shared may help determine whether the issue is related to the browser, generation settings, or a service-specific problem.
If you no longer wish to continue with the subscription, you can cancel it from your Adobe account:
https://account.adobe.com/plans
Because your Firefly Pro Plus subscription started on May 20, it may also be helpful to review Adobe's subscription terms, including refund eligibility and any applicable cancellation fees:
https://helpx.adobe.com/manage-account/using/creative-cloud-subscription-terms.html
If you decide to continue troubleshooting, please let us know the specific error message you are receiving and which Firefly video model you are using. That may help the community better understand what is happening.
We look forward to your update, @Tranquil_solution6a04.