After -sales service appalling!

The after-sales service has gone from bad to worse! After my recent installation in October, where the installer couldn't activate the Solarman app, I spent the next 3 months, on and off, trying to get them to fix it. Eventually I got someone to deregister the logger and I managed to get it working in 30 seconds. Last week I got a 3rd battery installed (the arrived the day after the original date, no communication, only not to have the right wall brackets). It was discovered at that time that one of the original 2 batteries they installed had been incorrectly linked and had been dormant for the 3 months. No wonder I had a battery issue and thought I needed another. On the installation of the third battery the invertor immediately showed completely erroneous and incorrect readings. The installer made no attempt to correct it, and it has now taken 5 days and being shoved from pillar to post even to get them interested in correcting it - adding insult to injury saying I would have to pay form the call-out.