No, the company contracted the service from another company, but that's irrelevant. I'm saying that in any case, the company is responsible for any service it provides unless there's a disclaimer. Be that service a chat bot, a ticketing system, a store, workers.
If an Accenture contractor fucks up, the one liable for the client is Accenture. Now, Accenture may sue the worker but that's besides the point. If a store mismanaged products and sold wrong stuff or inputted incorrect prices, you go against the store chain, not the individual store, nor the worker. If a ticketing system takes your money but sends you an invalid ticket, you complain to the company that manages, it, not the ones that program it.
It's pretty simple actually.