Wondering if their telephone solicitation is for real or will they take my debit card info and rip me off?

I actually don't have a complaint yet...but I received a telephone call from the Jerusalem Post in response to an email form I filled out because I was interested in subscribing.

They asked how I would like to pay and I said "debit card" but I was uncomfortable giving this information over the phone. The man said I could not subscribe on line. Why is this?