iPhone 5 can't make / receive calls while connected to Vodafone network

[ThisWayUp]

Hi,
 
My iphone 5 does not allow me to make calls or receive calls even though I am connected to Vodafone NL network (signal strength 2 - 3 bars).
 
If I make a call, I get call failed 9 times out of 10.  Sometimes, if I restart the phone enough I can make a call.
 
If I call my iphone from another phone, I hear ringing on the other phone, but the iphone does not ring.  Sometimes I then receive a text on the iphone to say I missed a call, but sometimes nothing happens.
 
I am missing out on important calls.  What can I do to resolve this?

[Maartje]

Hi ThisWayUp,

Do you experience this problem on a specific location? If so, please send me the exact zipcode. Then I can check for you what could be causing the problem.

[ThisWayUp]

Thank you for the reply.
 
I don't know if the service is different elsewhere as I rarely use the phone outside my house. I will check this.
 
The zip code is 1058 GP

[Serkan B]

Hi ThisWayUp,

I checked this for you and I see that our engineers are currently working with the network masts on your zip code. Try the 2G (GPRS) network. That should work.