The customer called in to report that their air conditioner was not cooling. I arrived at the customer's home and performed a thorough inspection of the air conditioner. I found that the air filter was dirty and needed to be replaced. I also noticed that the condenser coil was covered in dirt and debris, which was preventing the air conditioner from cooling effectively. I cleaned the air filter and condenser coil and tested the air conditioner to ensure it was cooling properly. The customer was happy with the service and thanked me for my help.