I have a 2 Degrees Mobile Broadband  USB Modem which has a MicroSD card slot. What is the largest most modern MicroSD card it supports that users have tried?

There is nothing on the 2 Degrees website (even though the phone message you hear says all questions are answered on the website). The telephone Help Desk said it supports up to 8 GB MicroSD or MicroSDHC cards but not MicroSDXC.  Can any users confirm this maximum limitation? I was hoping for a larger size of 16GB or preferably 32GB.  Has anyone tried the modem with a 32GB card?