That sucks honey. I remember when I went into labour (31 weeks) and my m/w rang Royal Womens in Melbourne (as I had to have DD there, not locally) and got one of my OBs and she told my m/w that they were too busy to accept me and that I'd just have to wait for my normal appt in 3 days.
So, I went to my local hospital and they admitted me and transfered me to Melbourne (via air ambulance).

Sometimes it just sucks. I'm so sorry that your little one needs more than Zantac. Having a refluxy bub isn't fun.
Hope you sort it out soon.