My refrigerater temp won't go below 55 degrees. Is

The air door "cold control" may be obstructed or the air return may be obstructed. The air return takes the air from the refrigerator section and delivers it to the coil. It must be clear for the fridge to operate properly. The cold control is just a door flap that opens and closes and allows cold air to enter that part of the cabinet. Open the cold control more and see if that helps. You should feel more cold air coming from it. If you don't then there's an obstruction.
If you have a thermometer that goes below zero, place it in the freezer. It should read 0 to -5 degrees f. If it doesn't then there may be another problem.