Might need to do more work and explain more?
Maybe the vacuum booster is not working? That will make for incredibly hard to push brake pedal.
Alternatively, the brake pads could be seized in the caliper. I have had that happen, and it was not quite as firm as a dead booster, but not by much (the rear calipers were still working).
Do you have "some" braking or zip? Do you have all the braking but it's just really hard to push on the pedal?