Why did Frontier get sued?

Can you explain the reason behind Frontier being sued? Was it due to a breach of contract, an issue with their platform's security, or was it related to some other financial irregularity? It's intriguing to understand the specifics of the lawsuit and what led to this legal action being taken against the company. I'm curious to know if there were any warning signs or red flags that investors and users should have been aware of prior to the suit being filed.