How can I call Nigeria from Malaysia? After I arrived few weeks I couldn't call back. Please help....

Hi Mustapha, to call Nigeria from Malaysia, you must have sufficient airtime on your balance, they charge you per minute not per second while roaming. Choose MTN preferred roaming network. The MTN Preferred roaming network in Malaysia is Celcom. Power off and power on your phone, you will be able to make call. If the issue persist, you need to contact MTN support.
You can contact MTN support via any of these channels:
1. MyMTN App
2. Facebook: @MTNLoaded
3. Instagram: @MTNNG
4. Live Chat: http://bit.ly/2OC5bHz
5. Email: customercareng@mtn.com
6 .WhatsApp: 09033000001