I have no need or want for Illustrator, and could always download images in the past and open in my old version of Photoshop. And now I need to have the Illustrator app to open an image? In other words, I am blackmailed into subscribing to another app. Time to say goodbye to Adobe Stock. I'm starting to see a lot of complaints with Adobe.
Hi Rita,
Sorry to hear that that you are facing issues with Adobe Stock services.
As Sheena Kaul mentioned earlier in her above post that vector files work the best with Illustrator only but can be used in Photoshop as a rasterised image.
However, if you do not have Illustrator, rather than subscribing the app you can always use the 7 day trial version(in order to use the vector file you have downloaded from Adobe Stock).
You may use this link to download the trial version of Illustrator: Download a free trial or buy Adobe products | Adobe free trials & downloads
I would request you to share the File ID which you are referring to so that we can check why you get a prompt to launch Illustrator app (ideally you should be able to use the image in Photoshop as a raster). If there is a problem with the file, we can check that and can fix the issue.
In addition when you are downloading the file from Adobe Stock please save the file to your desktop first and then open the file with Photoshop or Illustrator(trial version). Below is the screenshot:

Regards,
Twarita