Greedy and ineffective plumber

Avoid like the plague. Very expensive and basically ***********. Could not find the plumbing problem of a hard pressure hammer knocking when closing taps and when toilet cistern was full and shut off. Did not know what caused it or how to fix it. Put in a couple of unnecessary brackets which did nothing. Said to just close the taps to reduce the incoming pressure which did nothing. Left without even slightly improving the problem and then charged a ridiculous amount for callout and half an hour's work. Maybe I should have fixed a fee beforehand - so be very careful.