The Office of Consumer and Business Affairs is investigating unsatisfactory workmanship issues at two solar panel companies.
A third company Adelaide-based Unleash Solar went into administration this week.
Commissioner for Consumer Affairs Paul White will not name the other two companies now under scrutiny in South Australia.
But he said a conciliation conference was held on Thursday involving one of them.
"The company representative, it's an interstate company, flew in to Adelaide to take part in the conference," he said.
"They went out to the retirement villages which were the subject of the complaints, met with the people and I'm told they've said they're going to make good on all the unsatisfactory work."