I don't think this is legal, the Consumer Protection Act has this provision:
Estimates
10. (1) If a consumer agreement includes an estimate, the supplier shall not charge the consumer an amount that exceeds the estimate by more than 10 per cent. 2002, c. 30, Sched. A, s. 10 (1).
http://www.e-laws.gov.on.ca/html/statut ... 2c30_e.htm
So if they quoted one price, then charged another - you may have a legal recourse not to pay?