The type of customer service you’re thinking of would be outsourced to call centers by AirBNB. When you call a 1-800 number those aren’t actually employees of the bank/service/website usually unless the company if huge. Most of them outsource. I bet AirBNb really does have all those employees but they’re probably doing things like Compliance, Financial/Payment operations (chargebacks, disputes, fraud, etc) and a lot more manual stuff than people realize.