pairing a new classic camera to my network

I have just received a complete bundle and managed to add 3 cameras to my undefined, the 4th is proving to be a problem. I have had to charge it with Mains power as when i got to pressing the button in the pairing procedure under the waterproof cover no sound was being made. now when i try to add the device and i get asked to select my hombase it says it is already bound to the device and i cant complete the setup. I have looked in the undefined and i can only see the three cameras that i have already set up. Can anyone give me some pointers where to go next, I have tried to reset the camera and re started the undefined unit.

Many thanks

Andy