My city will respond and see if it might be their fault and, if so, do what they can. Another option I often use is a bladder. It's heavy gauge rubber and screws on a garden hose. Then push the bladder into the hole your dad made. Push it in where it's a couple of feet in and turn on the hose and it usually pushes whatever down the line. But check with your city's wastewater department first. It might save a lot of time.