sorry to hear that, can you elaborate on the "now it is not working" part? Can you still grab video over USB, see the orange LED, etc but only the hardware serial port is not sending anything out?
Have you checked that the arduino is 8N1 at 115200 bauds and that your TX/RX pins are not crossed?
Also remember that if you are not streaming over USB, then
1) you need to select a video mapping with no USB output
2) you need to manually start the camera stream by issuing a "streamon" command
See for example this tutorial:
the section on "running with no USB output"