Sai Service Station — Bike not serviced properly

I had given my bike for service at sai service bajaj kothrud i had gear slipping issue in my bike which i told them but they couldn't fix it, i again contacted them at first they denied the fact that there is a issue then they told me to leave my bike on a odd day of the week so that they can test ride my bike ... If they did so or not i don't have any idea but i recived my bike in even worst condition now i am also experiencing upshift problem very gery worst service by sai service bajaj kothrud i am really disappointed and angered