On my way back to Melbourne, I had a four hour layover in Qatar, so as soon as the GSM signal came back I sent Sabriena a message on Telegram (I know it's shit security, but her and her sisters like the stickers) to let her know we'd landed safely.
After clearing security, I went to check something else and noticed I had no data connection. I checked my Telstra account (which loaded, the first indication something was up) and found that despite having two thirds of my whopping 600MB "international roaming data" "plus pack" still available, I was out of credit and thus couldn't use it.
Why am I out of credit?
I checked the usage, and I had to pay three bucks to receive a spam call in Hungary, and I sent a couple of old fashioned SMSes, but that should have gone on my "International credit" balance ($200), much less eaten nearly $30 in base credit. Further into the usage, and I had to pay for those out of my base credit.
Furthermore, I had to pay for data several times out of the base credit as well, which adds up quickly... so what's the point of the "international credit" and the "international roaming data pack" if bits of it are just charged to my base credit anyway?
I'll have to speak to Telstra and work it out before the next time we travel.
Update: I finally got around to calling Telstra up at 10:28 on the 16th, spoke to "Mike" who informed me that it was indeed an invalid charge caused by a glitch in their metering system. They're refunding the base credit (not that I particularly give a shit about that) but more importantly it shouldn't happen again - the only thing I should have paid for were the couple of SMS messages I sent while overseas, because data was unavailable, and the phone call I received.