Hi Ladipo, to link a number on your Hynetflex one account,
1, make sure that the number is active,
2, It is not a beneficiary to another HyNetflex Sponsor,
3, The line must be on Hynetflex or Enterprice tariff plan.
If the line you want to link is not on HyNetflex or Enterprice tariff plan, you need to contact MTN support so that they will migrate your line to the eligible tariff plan.
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