Bad invoicing - no breakdown means you pay through the nose

So, about a month ago I had an issue with a leak and ended up contacting Super Plumbers as they were the fastest to respond. Booked the call and it came to about R 2000, which was not too bad. Considering it was a leak in the roof, which probably required climbing into the roof cavity and replacing or fixing the pipe or area causing the leak. I was impressed and kept their number. Yesterday my tenants let me know that the Latco valve had packed up on my geyser in the laundry area. Arranged to have someone come out again, and this time it cost me a whopping R 4500, NOT impressed as I know what the material cost should have been and time was probably about an hour and a half (was told weekends are charged the same rate as week). Some back and forth did not resolve the issue. So here we are - I ended up paying, but am not a happy camper at all. Asked for a breakdown, still waiting.