Former clients of a Canadian tech entrepreneur say they were let down after they paid his company tens of thousands of dollars to help launch their start-ups.People across the world - from Scotland to the southern states of the US - have told the BBC they paid Josh Adler's software company ConvrtX up to $245,000 (£184,000) but did not receive the websites and apps they expected.We spoke to more than 20 former employees and customers who say that Mr Adler continued to sell services and ask for mo...