Very poor service

We took our Ford Ranger to Ford Hatfield to be serviced. When we got the vehicle back it started giving problems with the engine and the vehicle started to lose power. We took it back and they then said that the fuse box and the glow plugs are faulty and needs to be replaced. We eventually agreed on this because they said that it would solve our problems. A week later the engine light came on and the vehicle started to lose power again. We took it in again just to find out that they are now suspecting a battery problem. I am trying to get answers from them but they are avoiding me and they keep telling me to leave messages without them coming back to me. We pay them every time just to find out that what they did, did not solve the original problem. To make matters even worse, everything started when they serviced the vehicle. The service is unprofessional and extremely POOR!! If you want to take your vehicle in for something do not use this branch, they are useless!!