dropped iphone 5s w/mophie x battery case into oncoming wave, few days in rice everything works except any connectivity, cell/wifi/bluetooth...etc.

dropped my iphone 5s protected in a mophie x battery case onto beach while running from huge oncoming wave. It was under more than 3' of moving salt water/sand mix and then receding wave for a good minute, I found it face up but nearly buried in wet sand. After few days in rice and removed from case, everything works on phone except any connectivity at all...just stuck in search mode, cell/wifi/bluetooth...etc. I have powered phone off and on, flicked settings like airplane mode off/on etc. no luck. Any suggestions?