I was dispatched to a customer's home to replace a faulty air conditioning unit. Upon arrival, I found that the system was low on refrigerant, which is a common issue. I contacted the customer and explained the situation, and they agreed to have a technician from their HVAC company come out to inspect the unit. I also contacted the HVAC company and informed them of the situation. I will follow up with the customer to ensure that the issue has been resolved and that they are satisfied with the work performed.