Continous Ringing

Problem with phone: Every time someone calls my Net10 number of 715-222-6022, then decides to hang up the phone, my Nokia 1600 continues to ring without ceasing. When I go to answer the call, not knowing that the other end has already hung up, the phone locks up and will only allow the power button to be shut off. Upon restarting the phone, it will continue to operate normally until the next call comes in. It will work fine as long as the calling party is still on the line when I answer my cell. However, should they hang up before I answer the call, it locks up as mentioned before.

I noticed the same problem with my other phone I have with Net10. But at some point it cleared up, but I'm not sure what fixed the problem. However this phone continues to be problematic.