Default Htc sensation 3g issues

Hi.Im from Macedonia.My phone Htc Sensation has issues with 3g network.When i decoding my phone 3g network is no longer conect on my One network only on Vip network.Same sim card 3g work great on another smartpnone.
Software information :
Android version 4.0.3
Htc sense 3.6
Softw.number 3.33
kernel version 3.0.16-g31a4fc7
Baseband version 11.76A.3504.00U_11.24A.3504.31_M

Can anyone help with my 3g network?Can flash radio band will help?