Hello Victoria,
Because there was a test sample it does not mean that the machine will still sew, it could have quite easily gone out of time at the end of the person sewing the sample, if it is not picking up the thread at all it will be a timing problem, take it back whilst it is still in warranty, you don't want to have to start repairing the machine at this stage.
drivewithken@blueyonder.co.uk, May 2008