First its not unusual for them to not eat with you at first. Your snake is probably pretty stressed out in its new environment. Wait a week without handing it. Give it some time to calm down and get used it its new home. If he/she continues to refuse properly heated frozen/thawed rodents you can try live.
Also in case you don't already have one you should have some way of controlling the heat output of your heat mat. Whether its a lamp dimmer from home depot or a thermostat. Its a pretty important tool to use as under tank heater burns on ball pythons are fairly common. You also need a good way of monitoring the temperature of your enclosure both on the hotspot and on the cool side. Infrared temperature guns are a great tool, or a lot of people use the dual temperature accurite thermometer from walmart.