GE REFRIGERATOR NOT COOLING PROPERLY?

Our GE refrigerator Model #GSS22WGPJCC is experiencing cooling problems. Ice cream in our freezer was found to be mushy, yet most other items were still frozen, despite hiking up the temperature control to the highest level. On the refrigerator side, the top shelf is not cold enough but fruit and vegetables in the bins down below were frozen. Can you help? Thanks.