Incompetent installation & poor service

The installation team didn't install sufficient support in the roof to support the solar panels so the roof sagged after 5 years. We now have to pay hundreds of pounds to repair the roof and add additional support. Their customer support is poor as it took us 3 months to get their team to remove the panels. They put obstacles in the way to delay the process and give them the option to not remove the panels. Their customer service department can't do much and are unable to pass calls to the appropriate department. Their legal team deny any liability about the installation but issue legal threats if we didn't comply with their rules. All round very unsatisfactory.