Hello! I had my car ( Golf6 1.4 TSI 160 hp) on Friday to change oil, because I wanted to saddle from Longlife (5W30) to fixed interval with 0W40. Then when I looked at the oil level in the evening to see if the friendly guy did everything right, I noticed that the oil level, measured at the track stick, is about 20mm above MAX and the supposedly new oil is as black/brown as before the change. But the oil filter was definitely changed. How do you think I should proceed? Is it possible that the oil change has not been carried out at all??? Thank you in advance!