Please help my phone was fine I was on mtn pay as you go and had to change networks so I went over to cell c and now it keeps saying phone not allowed mm6
Make sure your BB10 device is Unlocked.
If it was locked to the previous carrier, then it will need to be unlocked before you can switch carriers and/or use another carrier's SIM.
If it is, then contact your cell provider and request they help you with an Equipment Swap.