I found that zoton, I believe its prevacid for you, didn't always work for me and my GP came up with the following suggestion that really works.
First I take 30mg Zoton in the morning. I tried splitting the dose, 15mg morning, 15mg at night, but that didn't work. Then she put me on metoclopramide which I use to take at night and that worked really well. Unfortunately the metoclopramide didn't agree with me and I now take something else when I need it to settle my stomach down.
My GP told me that if we can't find a drug combination that works then I either live with it or consider surgery.
I am surprised that if your ph test showed severe acid reflux that surgery wasn't suggested as an option although they prefer you to try the medication first to see if you can control it that way.