Unit is repeatedly freezing up

Almost all dehumidifiers now have automatic defrost, but if you are seeing frost is just one small area, it means there is a refrigerant leak. Check your warranty to see if the sealed system is covered longer than one year. Generally, if it is, most manufacturers will replace the unit (rather than repair it, as the repair is rather expensive compared to the cost of a new unit). If you do not have any sealed system warranty coverage left on it, don't fix it. Buy a new dehumidifier.