No Stock of a required part for my Invertor for over a year.

Cube Nova Back Up Battery. I've been trying to get a solar panel from Ellies for over a year. It needs to be a specific one for the inverter as per their instructions. Even their customer care call centre does not escalate a complaint as they promise to do. What an absolute let down. I can't use my inverter for the purpose I bought it for. Won't support them again. Be careful before buying Ellies.