Solution not offered

I usually take my car for service at GWM Midrand.Took my car there about 4 months ago and I was told that the service was done and there was no need to bring it for a 50 000 k because it was attended to.Today I was told that Service Plan provider will not pay because I skipped the service.I tried to explain to the manager that I was missed informed by the staff member who was on duty on that particular day.The manager was not interested to here my side of the story.The point is I was missed informed and now I should suffer the lose which I think its not fair.There was no need for that manager to get so emotional on me.I wanted him to listen to me and possibly come up with the solution.Its not my fault that they keep on changing staff.<br> He does not have customer service skills.He should have calmed the situation instead of defending himself and the company.