Roaming Voicemail Charges Problem

My apologies in advance for this long boring post! But there's unfortunately no shorter way to say this.

Telenet is charging me for incoming calls (roaming outside EU) even when my phone is off and the calls are not answered but roll to voicemail, and even when no voicemail is left by the caller. These calls last for only a few seconds - typically 4-5.

I called Telenet, and the tech told me that that is correct, and the only way to avoid the charges is to turn off voicemail before leaving Belgium, and to turn it back on again only after returning to Belgium. In addition, I cannot turn the phone on even once to check incoming SMS's, as the SIM card will then know where I am, and I will be charged for these unanswered calls until I return to Belgium, as described above. And to add insult to injury, I cannot turn voicemail off and on myself on the Telenet Web site, I actually have to call them on the phone to get it done - amazing! Hello! Talk about a klugy, backwards system!

So, for example, if I spend a month in Singapore, and get ten unanswered calls a day, when I get home, a factuur of €420 will be awaiting me, thank you very much. This is totally and completely way beyond unacceptable. Sure, I get a Singapore SIM card and local number, but it's impossible and impractical to attempt to advise everybody who has or has ever had my Belgian number to call or text me on my Singapore number - utter madness!

I may not know much, but this I do know for sure: I can't be the first person in Belgium to have this problem.

So the question to the blogosphere is simply this: who has also encountered this problem, either with Telenet or any of the other Belgian providers, and what clever solutions (if any) have you found? How do providers other than Telenet handle this situation?

Thanks so much!