We have a thermostatic mixer shower and we are not getting any cold water coming through. We have tried loosening the mixer heat control but this hasn't helped ?
We are also wanting to turn off the water supply and need advice on how to do this.

Some showers are built with an access door behind the shower in the next room like a closet. Rare but worth checking for a door or access plate. Short of stop valves behind a door you can close the incoming water main to your home. Tell us the brand and model valve you have and we can help further. Could just be junk in the cartrdige.

MettyGirl,
What kind/brand of faucet is it ? It may be adjustment nut / screw that slipped out of its position. Back to you. Milo