I have been trying to call the Overland Park Ks location for 3 days and can not get through. I need a replacement power supply for a computer purchase for the above location. The power supply is a HEC-250CN-2RU. It is very tight in the case and the mounting screws and harnesses need to match exactly. What part number is on hand at the Overland Park Ks location which will cross with the HEC-250CN-2RU which is bad?