My Clearblue Advanced digital ovulation monitor stop showing the screen after the 8th use.

I bought a 20 tests Clearblue Advanced digital ovulation Test. I was using the 9th test this morning. When I inserted the test sticks into the digital monitor. It was supposed to blink, but it does not at all. The screen does not show anything. I am guessing the monitor is out of battery or broken. What should I do? I need a replacement of the monitor.