Found this a little later.
This was a link on GM.CA
If you have a question, comment, or problem with a product or service, let us know; we will be happy to serve you.
Our Customer Care Centre hours of operation are:
Monday to Friday: 8:00 a.m. to 11:00 p.m. (E.S.T.)
Saturday: 8:00 a.m. to 5:00 p.m. (E.S.T.)
Product and Program questions :
1-800-GM-DRIVE (English, Cantonese, Mandarin)
1-800-463-7483 (French, Cantonese, Mandarin)
Customer Care Centre:
1-800-263-3830 (TDD users)
Cadillac Customer Care Centre:
1-888-446-2000 (English, French)