It's pretty much normal in a call centre environment to ask if you can address people by their first name. Some people, especially those of older generations, and some cultures, find it really disrespectful to be addressed by their first name.
Yeah this... generally at Telstra we would ask your full name and then would say may i call you "jacinta" even if you only gave your first name we could still see your account details and were still generally advised to ask.