I would first ask the customer if they could provide me with more information about their issue or concern. If they still insist on speaking to a manager or someone higher up, I would politely inform them that I'm the first point of contact and that I'm happy to help them with their issue. I would then listen to their problem and do everything in my power to provide a solution or escalate their issue to the appropriate person or department. Also, I would ask the customer for more information about their issue or concern because it would help me to better understand the situation and provide the best possible solution. It's important to listen to the customer's concerns and show empathy for their situation. If the customer is still insistent on speaking to a manager or someone higher up, I would politely inform them that I'm the first point of contact and that I'm happy to help them with their issue. This shows that I'm willing to help and that I'm taking their concerns seriously.