Iphone 3gs help!!

[arisblind]

ok.. for some reason whenever someone calls me, my phone doesn't ring, i dont know why, but my sound on the phone is perfectly fine, i can hear it when some1 text me, play utube videos, play games... its just that whenever some1 calls me it doesnt ring... can some1 please help me

thank you

[sabbireyephone]

how can i jailbreak my i phone 3gs. my software version is 4.2.1