How can I retrive back my wallet pin

Hi Chinedu, do you mean your MoMo wallet, you need to contact MTN support for them to reset the wallet pin for you.
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