I had the same problem. I even sent the first keyboard back thinking it was faulty. The replacement I received was the same. I went in settings set everything right. Still the same. I had to press shift and number 2 I believe to get the @ sign. The thing is I couldn't even tell you how I sorted the issue. One day I had keyboard options pop up on there own. I clicked the setting it asked me to change to and the keyboard has worked ever since. Just popped up after a few weeks. So I'm guessing it's got to be in the settings somewhere. I wish I could remember what notification setting popped up. When trying to look in settings I never found it myself to correct the keyboard. But it's got to be there.
yes did all that no change. i've contacted Samsung and the second person i spoke too, (the first just wanted to fob me off) well the second person, tracked the problem to an App, don''t know which one as ive ended up doing a factory reset and now downloading each app then testing. but at least problem now solved