I know very little about share play and can't really help. The only thing I can think of is that you need to have solid internet on both sides. Are you located geographically close to the person you're trying to share play with? But I don't think this is the problem, because I've encountered that issue and it still let us try.
I went to google and searched "PS4 share play guide" and I got a lot of hits. Try it out.
I think the help desk was mistaken to send you here. Besides checking google for solutions, as I suggested, the next move would be to go to PS customer service, as this is a PS feature, not EA.
.JPG){kind=link}