I subscribed to a Pro Plan, and the offer claimed I'd get free generations, unlimited, using certain models. I attempted to generate a video using the Firefly model and was told I had no credits and had to pay for more. What is the offer good for?

I used up all my credits that I am allotted with the Pro Plan, yet the offer I was promised was unlimited generations thru Apr 22 using certain models. I attempted to use the Firefly basic video gen model and was taken to the “pay more’ page, told I have no more credits and can’t generate any more unless I upgrade to the pricier subscription. So what models are free to use to generate unlimited images or videos?