Photoshop CC 17

Please can you help?

My Photoshop CC17 App has been behaving strangely, so I followed the advice to uninstall/reinstall. It has now disappeared without trace and I cannot find a reinstall link anywhere (even via adobe chat). 

I am running the app on a subscription basis on an I Mac with Yosemite OSX 10.10.5. It was working fine yesterday but now no longer exists. It seems a bit unfair when I am paying for something I cannot use.

Please help by providing a direct link for a reninstall if possible. Many thnaks in advance. DM