I don't know if it's a female thing but my step daughter got robbed in a simialr way by a dodgy garage. She took her 125 Marauder in for new brake and 4 months later received a bill for hundreds of pounds for everything including replacement engine and still the bike doesn't run properly! She got all sorts of excuses, even blaming her for the shit service she is getting! They seem to think that females know nothing and are an easy pushover. Show them you are not! A business with no card machine or receipt system is always dodgy to me. Ask the questions next time and in the meantime ... as above, CAB and inform HMRC office. They will be fooked from conning the next customer.