2014 Heater Assembly Replacement Nightmare

The Volt uses a heater system that is complex and expensive to replace. It uses a heating system which relies on an electric heater to heat up coolant that is going through the coolant line. The heated coolant is then sent to a pump which then provides heat to the cabin. Without an in-line coolant heater, the system does not work and requires the replacement of the in-line coolant heater (also known as GM part no: 22851153, 22747764, 22788440, 22792167, 22794426)

I have been trying to fix this problem by first going to a local GM dealer, only to find them asking 3800 dollars for replacement of the inline coolant heater and heater pump and the 8 hours of labor it takes to get access to the parts and replace them. Just the in-line coolant heater alone would cost 1700 dollars. I did find a new one on GM part exchange for 1000 dollars. I don't have that much available to spend on repairs so I then found a local mechanic that would be able to use parts I found on Car-parts.com-a used car parts online search service.

That lead me to Green Light Auto in Southern California, where they had the part listed including the correct part number. Only problem is they ripped the part off and the High Voltage wire and connector were missing when I received the part in the mail. The wires cannot be spliced according to a certified GM Volt tech because that could heat up and start an engine bay fire.

So back I went to look for another replacement part, and there are not many used in-line coolant heaters available anymore (even though they are interchangeable through all Gen 1 years). The next place I called still hasn't returned my call, my car-part.com price quote, or any of my emails. All I wanted to know was if the part they list on their website and on car-part.com is actually the GM part number I listed earlier.

So now I'm stuck buying the $1,000 plus tax in-line coolant heater new (can't afford) or just buying the power inverter kit that is on this forum and plugging a space heater into it which all together would cost $500. Which is the best way to go in this situation, and has anyone else dealt with this? Been a Volt owner for over 2 years and it's a 2014 Volt with 111k miles.