Quoting prices excluding vat without notification

I requested a quote for a electrical clearance certificate , the quote was for R250.00 call out and R650 for the certificate . I agreed to the quote and made arrangements for the call out , on completion of the job my partner was presented with a bill for R1026.00 now claiming that vat needed to be paid . On querying the invoice i was told that the company is vat registered and they have to charge vat , when i explained that it was against the law to quote prices ex vat without making the customer aware of it . The owner responded that i should not tell him how to run his business . He now refuses to issue me with the certificate .