Firefly eats credits and generates nothing usable

Yesterday, I start generating some videos to try Firefly. It generated non-usable 5' videos... and it ate more than 50% all my monthly credits! (only trying som tests) So... It ate 400 credits for 1 video only... and can't even using it*

* I tried a walking white horse and Firefly generated it... but the horse walks strangely and unnaturally. Instead of walking, it seems to jump with all four legs together... The result: weirdo and unusable.

At least try to eat less credits.

What do you think?