both are mobile phones are saying network busy from yesterday if you try to ring them just getting engage tone they ring once & then go off cannot ring out either can only text please help thanks

You could try taking your sim card out and wiping the contacts on it, but to be honest it sounds like a network issue, what network are you on.

tmobile on phone to them now they are trying to find out what it is

Had same problem, switched airplane mode on 3 seconds and back off. Perfect.

I had same problem
Switched off 3G and to only use 2G network, solved problem
Still, it doesn't explain why