Bad Service: Autowise

I went to get my vehicle fixed because there was a knocking sound while driving, i was told it was the shocks that needed replacement(I paid 7.8K). i approved for them to replace them however the sound was still there after collecting the vehicle. i complained & took the vehicle back and now they are telling me its the wheel bearings that need to be replaced and that i need to pay for that also. they refuse to fix what they misdiagnosed and REFUSE to correct their mistake. they have no manager on site and refuse to let me be in contact with one.