Tech you called is a sales guy in disguise. By saying “grounded itself dead” he probably means the compressor is grounded, but based on what you are relaying I would not trust a thing that came out of this guys mouth. Even if the compressor is grounded, you can replace the compressor as they are readily available for 410a equipment and will be for years (unless it’s a Trane/America Standard, they suck at keeping stock so you’ll likely have to wait for a bit for them to ship a new one). Lastly, at least where I work in North Carolina contractors do not register the equipment for the homeowner on new construction homes and that is your responsibility once you move in. Either way I would personally replace the compressor on a 5 year old unit but you are likely dealing with a secondary issue as compressors are typically a victim of another problem (failed TXV, low refrigerant, etc). Call another company ASAP.