Inverter firmware issues

I have 2 inverters (soliax5p) in parallel both were running version 74.30. Unfortunately after the units had to be repaired due to the PV+ ***** breaking, the one unit came back with version 72.20. Now they will not parallel due to version conflict. I have contacted Treven and Manny to assist. After a few days they still waiting for Andy (Voltronic Taiwan) to send through the firmware. I decided to phone Andy myself, he says the unit firmware cannot be upgraded, they need to change the control card back to the original version. Why am I getting the runaround? I am very frustrated ?