Is the heat mat controlled by a thermostat? If not unplug it immediately and get a thermostat; without one it's a burn hazard.
The bare minimum your snake should have is a thermostat controlled warm side with a hide, a cool side with a hide and a water bowl. You can use paper towel for bedding. Humidity should be between 50-60% and should be bumped up during shed. Humid hides can also be used to aid in shedding. Warm side should be between 88-92 and the cold side should be around 80-82 degrees; the snake will thermoregulate its body temp.
Until you fix your husbandry you will continue to having feeding issues.