Number of Belgacom

Hello - my Belgacom mine has been blocked (I think I missed a bill) so I can only receive calls and not make them. But I want to call and verify the issue and the bill before I can do anything. How the hell am I supposed to call them and ask? Stupidly, even the 0800 numbers for questions about technical problems and bills "n'est pas authorizée" Does anyone know of a toll free number for Belgacom that will work no matter what? I don't exactly want to call form the gsm knowing that the average time you are on hold could be easily upwards of half an hour.