Thanks for the information. My keyboard also disappeared and I couldn't get it back, no matter what I tried. I called customer service and she didn't even know what it was. She did try hard to find out, but while I was waiting for her to come back on the phone I googled the problem, and this is where I landed. So I restarted my phone and when it came back on, there was the keyboard. I still don't know what I pushed to make it disappear, but this same thing has happened to me twice now, and it's good to find something that works.
And Thanks also for the post with the picture of phone screen with Push and Hold circled. I just tried that and now I know what I was accidently doing to make my keyboard disappear. Now it seems really Duh! Thanks a lot everyone for your great answers.