McCarthy VW over charge

I took my car in for a standard 60 000km service. I have a Polo 1.6 tdi and normally service at VW Hatfield in Hatfield. I thought I will try the McCarthy VW Wonderboom branch. I was greeted by a service advisor that told me how expencive this service would be. My mistake that I never called around for quotes. The company charged me double in labour for the same service that VW Hatfield written quoted me after the weekend- so from R1001 to +R1900. Parts prices was more or less the same but is VW SA not supposed to govern this time of behaviour -overcharging on labour? It's already tough enough to keep up with the price of servicing your car to keep the warranty- then to get exploited like this. <br> How can they justify that for labour on a simple oil and filter change service?