Doesn't matter if he is a sole trader. Small claims courts deal with all manner of disputes from ones like yours to who is responsible for someone tripping over in the street.
You can't take money off people for goods/services, then not supply said goods/services, with impunity because you are a sole trader.
You can't take money off people for goods/services, then not supply said goods/services, with impunity because you are a sole trader.