You can make calls but not receive calls and why your phone rings somewhere else when someone dials your number

You can make calls but not receive calls

1. Your line may be manually forwarded to another number by mistake. Single line telephone users: pick up handset, hear dial tone, press #71, hear special confirmation tone, hang up. Multi line telephone set users: press CFW key to cancel the Call Forward feature. The indicator light will go off. 
    
2. The ringer may be turned off for your set.

Why your phone rings somewhere else when someone dials your number

Again, your line may be call forwarded to another number. Single line telephone set users: pick up handset, hear dial tone, press #71, hear special confirmation tone, hang up. Multi-line telephone set users: press CFW key to cancel the Call Forward feature. The indicator light will go off.