Between a chat bot and a human, it's a really hard choice, but I'll still have to lean towards the flesh sack, despite the lack of knowledge, they can be reasoned with, they have emotions that can be manipulated, they can feel sympathy towards your problem. AI will have none of this, in exchange you'd potentially get knowledge backing the responses, if programmed correctly, which is the main issue there, they're be programmed deliberately to be unhelpful, with limited responses and no way of actually using their AI to help you with your problem.
Amazon being a perfect example, the chat bot there is completely useless and only helps with what you can do yourself on their site, when you have a real problem, you still need to get a human on the other end, and so far, they've always helped me.
However I've also had absolutely horrid customer service from useless sacks of flesh who shouldn't be breathing, let alone employed. Samsung's customer service and Bestbuy's Geek squad, what a hot pile of garbage those customer service representatives are, I Can tell you this much, if you ever consider buying a refrigerator from Samsung, run, don't walk, away from it. And if you already have one, you'd better have an extended warranty, because the base 1 year warranty with Samsung is worthless as they can't fix their products to save their lives. But I digress.