Aircon repair overinvoicing.

Our aircon stopped working, i looked in Google for a repairer and called a company called Chris Hvac. A technician arrived a day or so later and spent about 40mins at the property. The aircon worked again. I received and invoice for R 4050 where R550 was charged for a service, R650 for a regas and R2850 for a start capacitor replacement. I enquired with friends in the business and established that the Capacitor cost R175 plus vat so in essence a further 2500 was charged to fit it. I took issue with this and the exchange became acrimonious when the "supervisor" a man called Arthur accused me of being a ***** and made a veiled threat about "people living in glass houses shouldnt throw stones" I offered to settle the account at a fair price and in the end paid 2k which was about R400 more than i was subsequently quoted from other aircon people for the same job. Bad news company this.