MTN sim card issue

[phoenix99]

I have an older sim card in my phone,not sure which, but even when my phone shows 3g available i can't connect. Do I need to get a 3g sim card? I'm on top up

 

[upup]

yes

 

[10i]

A few questions for the sake of clarity:

1. What make and model phone do you have?
2. Can you make and receive calls, send SMS?
3. Is it only when trying to use your phone as a modem that you have problems?