The answer is when you are on a old Snap plan.
I joined 2degrees mobile on a $29.95 monthly plan thinking, since i was on 2Degrees Broadband plan i would get the $10 a month off my plan as stated on the Website
"If you’re on 2degrees Pay Monthly & Broadband, you’ll get $10 off your monthly Broadband bil". I rang up 2degrees to tell them only to be told that since i was on a old Snap plan i dont qualify for the discount, even though im a 2degrees broadband customer. They said i had to cancel my plan and join the new 2gegrees broadband plan which worked out to be the same price. I wish they made this clear on the website before i joined the mobile monthly plan. Has anyone else come across this policy.