RS Plumbing no integrity no approved quote

RS Plumbing Services operates in the Edgemead, Western Cape region. Robert Shearer came onsite to fix a burst pipe. On arrival, I requested a quote before any work was done. He said to me that it won't cost a fortune and proceeded to work without me approving a quotation. Further to this he took his team away to an other site and returned to complete the job later that day. My concern is the ridiculous invoice. The material cost was minimum yet he billed us for extra hours. I work from home and witnessed that they did not take as long as they billed. I am concerned about Roberts integrity for overcharging clients without getting an approved quote. Now he refuses to review the invoice and demanding payment. Edgemeadians, please be wary of RS Plumbers.