I must pay for repairs on guaranteed watch

I bought a police watch at Edgars in August last year I had it four months and played golf with it on once in the rain and the light stopped working and it fogged up completely even though the watch is supposed to be water resistant. It is still under guarantee so I sent it for repairs they sent it back and all they did was clear the face of fog didn't't fix the light. So I sent it back now they say the light isn't under guarantee I must pay for the repairs. That is the most ridiculous thing I've ever heard from both police and Edgars really poor I've been without a watch now for 3 months