Elastix in high availability can be very complicated, since HA is not built in the system but rather bolted on by the consultant installing the solution.
I know, I have installed quite a few Elastix HA solutions and they were not easy to setup, however some of those installs have more than 5 years running like a charm with thousands of calls a day.
I can take a look at your system and fix it in a few hours. After that, if you like, I could do a complete review to the system and maybe suggest some improvements