Hi there Millie11,
Welcome to the eForum - you've certainly joined with an interesting question
As Cartman_81 has said, a normal Pay as You Go SIM will have the wrong APNs (Access Point Names) set up for the dongle so the charges could be different/higher.
We normally don't migrate contract boradband over to Pay as You Go - you'd have to buy a
Pay as You Go Modem instead which would also come with your first 1Gb of data
I'll check around a bit and see if we can change the APNs for you though and get back to you on here as soon as I can
We cannot change APN's on a normal PAYG SIM. At the moment the only way to get PAYG Broadband is by buying a PAYG modem.
Paul
eForum Team