I was having some trouble the other day getting phone number extensions to work on my SEM ads, instead they were displaying my sitelinks.
Because for this client it was really important that we get the phone number live, I did a bit of playing around for a few hours to try and make it work. I found the answer, but it seems like a bit of a work around.
The answer is that it doesn’t seem like Phone Number extensions and site link extensions like playing well together, with in my case the sitelinks having a dominance over the phone number extension. In the end all I did was duplicated my campaign, changed my old one to only target computers and tablets (as tablets don’t usually have call functionality), and in the duplicated campaign (mobile only is what I called it) I targeted only mobile devices. I then removed any sitelinks from the mobile only campaign (whilst ensuring that the phone number extensions were still there) and that ended up working for me!
Hopefully if anyone else comes across this issue it will help them out as well!