Cheap...you should get that for free.
You can fix it, but it will be a bit of work. The most stable fix would be to totally recut the front panel at proper height and then add panels to the sides to get it to height. You would need to put cleats on the inside of the cab to attach the side pieces. I would recommend at each joined edge. The newly-cut front would provide enough rigidity to keep the assembly stable. Use both biscuits/glue in the joined faces and screws through the cleats to join the pieces. When the joint is sanded and sideart applied, you'll never notice the repairs.