@Octavian Welcome! I can imagine that this is very annoying for you. I don't think I understand you correctly.

• Do you have an ‘Alles-in-een Standaard’ ,
  • Internet, tv, landline
• or do you have a  ‘Zorgeloos Standaard’ ,
  • mobile contract, 1 or 2 years 
• or did you buy a prepaid bundle? 
  • prepaid simcard

If it concerns a mobile phone, did you enable the roaming function within the settings of your device?

Hello,

I bought a prepaid bundle (I have a prepaid simcard) and I enabled the roaming function. 

Kind regards,

Octavian

Thanks for your fast response. Could you please update your personal profile with your phone number? This allows me to check some settings from our side. 

Thank you for your fast answer. I have done it. Please let me know if you can see it.

Kind regards,

Octavian

@Octavian Thanks! I can see your number. I can't immediately find the cause of this problem. According to my system, you should be able to call to Belgium. You do enter the land number (+32 for Belgium) before you enter the mobile/landline number? 
What type of device do you use? 

Hello,

I called using the full number with +32.

My wife faced the same issue and she managed to solve the problem by buying additional credit.

This is how my bundle looks like.