75k Service: Poor Performance

After a 75k service at Kia Centurion, my car seems more sluggish then ever.<br> After reporting to Kia centurion the lady was quite adamant and informed me that they fully booked for next few ,months. Based on the performance of the car it feels like parts where not even replaced. Kia should have made an arrangement as I was dissatisfied with the service and gaped me in .There should be a procedure for people with comebacks<br> I have a maintenance plan on this vehicle up to 90000km.<br> <br> Please I need this attended to urgently as Im always on the road.