Unable t get incoming calls

[Avez]

Dear sir,

I have been using sony xperia SL for 2 months. I have a problem. I am unable to receive calls while surfing internet. the problem is even with the messages also. While downloading and surfing internet, i am getting this problem. I am using Vodafone sim. I made a call to them and they asked me to check the device.

Please help me through this..

Thanks

[Henke]

When you are online, on what network:  GPRS, EDGE or 3G?

Have you tried another SIM-card? Also from another network provider?