Cell C
No calls, internet connection Iphone 5

I have a Cell C contract on the Iphone 5, but can't make/ receive any calls and have no Internet connection. My service provider is Nashua Mobile, but I have sent it in for repairs at them, and have done a sim swop twice. The contract may be via Nashua Mobile but it is still linked to their services. The contract is useless if Cell C can't provide cellphone coverage for the phones they are selling.

I am past the point of frustration. Please help.

Renske van der Vyve