depends on what network your on, i've had plenty issues on metro since upgrading to this phone last year on stock. every single call i'd answer would drop unless i walked outside, sending text's didnt work unless i'd power down the screen(because if i held it while on i'd get no service... would have to push power and let it sit for 5 sec and service would come back), so what i'd do is type out my msg and send then shut screen off set it down, then check if it sent lol
if your not on stock make sure your using the correct modem