When your company is small you have few customers and your structure is simple, so you hire one assistant to handle all customer support and that assistant has enough time to process each request with attention, and she has enough knowledge and authority to solve non-trivial problems in creative ways.
When your company gets big, the amount and complexity of customer support needed scales disproportionately, and it stops being possible to process each customer in a meaningful way, so the whole thing becomes a game of leaving the least number of customers dissatisfied.
When your company gets big, the amount and complexity of customer support needed scales disproportionately, and it stops being possible to process each customer in a meaningful way, so the whole thing becomes a game of leaving the least number of customers dissatisfied.