Poor workmanship

I bought my 2016 Ford Ranger from Woodmeed Ford and had it serviced from the start at Silverlakes Ford. Since the first service I have been complaining and requesting that the gearshift is sticky and that it must please be sorted out after the 75000km service I took it back and did not ask told the workshop manager and the technician to sort it out, and I received so much bad attitude from a lit of the people working there, even one of the secondhad car sales men told me to take my vehicle back to Woodmeed and go and complain with them... How ever I started with the 90,000km service this evening myself, because my service plan expired in May this year. On cleaning the outside of the sump plug before removing it I noticed silicone sealer on the plug, which made me think! While un*****ing the plugit turned very hard, unlike I am used to, usually it can be turned by hand once it has been loosened. When it came out, the thread was badly damaged, which means that at one of the previous services it was *****ed in incorrectly. What's concernig me is, has the engine oil ever been replaced?