HTC sensation XE

Hi everyone , i've bought a secondhand HTC sensation revolution S-off HB 1.27.000 , update pyramid-ota-eng.pera-build-3 no problem . but since then my signal keeps getting lost when i put my sim card in it reads the sim and says the network operator at the top but it wont text or send or receive calls , but internet and apps work completely fine.

How do i solve this problem?!

Thanks,