Re: Used and Abused.
Is there an equivalent of a small claims court in Canada - somewhere you can seek arbitration for a small fee? With the lack of any written contract and no evidence of a verbal contract trying to seek credit for your performance is unlikely to be successful but there might be a chance he's willing to pay up something of a performance fee.
Better pray they don't have any sort of success - it would be appalling if they actually started selling records with your playing on it :/
Lessons learnt here - either do these things as a favour for friends; do nothing with out a contract and/or take fees upfront.