New front tyres on k13 dig s

Hi can anyone help,
I have just had 2 new tyres fitted by local kwik fit dealer.
Before I took the car in my steering wheel was always central when driving straight ahead, since the new tyres have been fitted my steering appears today be offset to the left.
The car has been back in 3 times and the tracking checked with no success.
They have even changed the rear wheels to the front and now the wheel is offset to the right !
Anyone have any ideas ?