A lot of it may have to do with the province you're in as well. In British Columbia, according to the Business Practices and Consumer Protection Act:
116 (1) A collector must not communicate or attempt to communicate with a debtor at the debtor's place of employment unless
(a) the collector does not have the home address or telephone number for the debtor and the collector contacts the debtor solely for the purpose of requesting the debtor's home address or telephone number or both,
(b) the collector has attempted to contact the debtor at the debtor's home address or telephone number, but the collector has not contacted the debtor in any of those attempts, or
(c) the collector has been authorized by the debtor to communicate with the debtor at the debtor's place of employment.
(2) The collector must not make more than one verbal attempt, under subsection (1) (b), to contact the debtor at the debtor's place of employment.
Here is the full reference:
http://www.leg.bc.ca/37th5th/1st_read/gov02-1-pt07.htm#part07-div01
-Ryan
116 (1) A collector must not communicate or attempt to communicate with a debtor at the debtor's place of employment unless
(a) the collector does not have the home address or telephone number for the debtor and the collector contacts the debtor solely for the purpose of requesting the debtor's home address or telephone number or both,
(b) the collector has attempted to contact the debtor at the debtor's home address or telephone number, but the collector has not contacted the debtor in any of those attempts, or
(c) the collector has been authorized by the debtor to communicate with the debtor at the debtor's place of employment.
(2) The collector must not make more than one verbal attempt, under subsection (1) (b), to contact the debtor at the debtor's place of employment.
Here is the full reference:
http://www.leg.bc.ca/37th5th/1st_read/gov02-1-pt07.htm#part07-div01
-Ryan