Welcome to the Community @wohny
Your topic is similar but different to this older topic that might be instructive into the trials/frustrations that may come into play, about a dealer using a non-approved lubricant.
Have you brought your concern to the dealer for rectification? For context was the discrepancy a major or minor issue? For example not changing out a cabin filter or not checking tyre pressures would be a different concern as compared to failing to change the oil, to make a point.
Should you have a related warranty issue that stamp should put the onus on the dealer but the reality is if the service was not correct you may have to go to a tribunal for satisfaction IF the manufacturer and/or dealer will not stand behind the warranty.
You should have received a line item statement from the dealer regarding the service, and that should reflect the normal service schedule. Is that your point of comparison or did you observe the service did not reflect the statement, or something else?
