Open Question: Non-refundable deposit in Ontario?

I put a $20 non-refundable deposit down on a pair of shoes. The receipt was written out with a total of $70 dollars outstanding for a grand total of $90 for the shoes. The clerk told me my shoes would be available for pick up in 2-7 days. A few days after I ordered my shoes the clerk phone me to tell me that she had quoted me the wrong price and that the shoes would be $30 extra. On top of that it has now been 6 weeks since I ordered my shoes. Am I entitled to getting my $20 deposit back or is it truly non-refundable?