Unauthorized replacement of my geyser

On 17/2/16 at 8am, I called Discovery to report my leaky geyser. Discovery's appointed plumber contacted me shortly thereafter and asked me if they could send a plumber to assess the geyser. On 18/2/16 at 8am I contacted Discovery to find out if I could cancel the claim and I was told to complete a withdrawal of claim form I said I wanted to wait until I received the quote and report - if we could do the work cheaper we would cancel the claim and no work was to be done until we gave the go-ahead. At 2.29pm I received an email authorizing the replacement of the geyser. I immediately sent an email to Siphelele asking her to contact me as I had given Discovery explicit instructions not to proceed with the claim I was shocked to hear that the geyser had already been replaced. I requested the claim be removed from my claim history as at no point in time did I authorize this work and to date still haven't received the cost of this work. R Herman & T Mtshali claim the mandate allows the plumber to proceed without Discovery's approval. The plumber did not receive my approval and Discovery is refusing to hold him accountable for unauthorized work. Very ********* behavior.