kumquat, I get phone calls or e-mails quite often from my credit card companies when purchasing overseas. I do not find it unusual for them to call me. Their transaction systems pick it up as unusual or suspicious activity. It is a safeguard for both them and myself. Many times I will call the credit card company in advance to let them know of an overseas purchase so they can notate it in thier systems to avoid the e-mail or phone call.
In regards to strawberry.net, ask the members in Asia or South Pacific what they feel about them, their service and validity. You will find they have a very positive following.
The reason they are asking for some sort of ID is the same reason the CC companies may flag an unusual purchase, to protect themselves.
Even in the US, you sometimes have to provide a utility bill to prove who you are and that you are indeed the person living at that address, so I do not find this unusual.
What I find unusual, is the CC company telling me they will freeze my account if I do not cancel what was a legitimate purchase.