How do I recover my long lost mtn number

Hi londiwe, you need to confirm first if the number is still available for you to retrieve from MTN support. MTN recycles a dormant line after 365 days.
find below MTN Nigeria Contact 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
7.Call: 180