Quoted for service, added parts without authority

I took these guys an overlocking machine to have the timing re-set. was quoted R350. On collection the bill was suddenly R556 - new blade, new bulb - not asked for (the blade price was 5 times what I paid for from the empisal supplier) . I politely asked that they remove the blade and bulb as I have these items myself and Paul refused outright. (When I went in he was the friendliest guy in town, but his attitude turned arrogant and downright nasty) - I actually thought he was joking. I have sent this to my legal insurance guys and am still deciding whether to take it further. But be warned, ladies especially, it's not the first time I have heard of this practice. Whatever happens, old Paul's day will come - he appears to be a rather unhappy fellow anyway, so good luck to him and his business.