Change the model for using Credits.

The current model of taking credits that a user has paid for and not providing any useful footage is not acceptable commercially.

This might have been the case in the early days of Firefly but not now on a fully released service.

If there is concern about users downloading videos (from browser tools) without payment have you considered the same model that Music Libraries use - to ‘Watermark ‘ end result before it is paid for then downloaded?.

Why not Watermark a video (generated from text or first frame image) in a way that allows generated content result to be verified, but not used as the Watermark would prevent that?.

Perhaps the watermark may need to randomly change throughout the video to make this more secure?.

Once a user is happy with the result and on payment of your credits,  the final end footage/image may be downloaded correctly.

Arguing that server time needs to be paid up front is no longer going to be accepted by users as they will use competitors instead and your user base will evaporate.