Why the option for switching data on my Xperia C5 grey.

[Android Central Question]

Hi,
I've been updating my Xperia C5 software to the latest version, but after that my sin card slot been acting up it only can read my main sim card so all data traffic goes there, even I have put the new şımardım for data traffic, still it can't detect it.
Iike before I did the update, I can switch on the data traffic at anytime I like.

Kindly help...

Thanks.
Fara