try to answer a call on my S4 and it immediately disconnects

[AC Question]

I can't seem to answer a phone call. I receive a call, I swype to answer and it connects for about half a second and then disconnects. I am using a UK Vodafone sim, but im not in the UK, I have credit on the sim. I can send/receive txt. I can connect to wifi (i don't use data). I can make a call, I just can't answer one. anyone got any suggestions?

 

[B. Diddy]

Welcome to Android Central! Have you spoken with the company that provided the SIM?