Thomas Griner Biopulser I sent back my biopulser machine that I purchased for $600 from this company with an additional check for $50 for repair and he kept my machine and never sent it back and he blamed the post office and Internet

I purchased a Biopulser machine from Healthy Muscles LLC aka Thomas Griner for $600. The machine broke and I was told to send the machine back because of a recall on some faulty parts. Because of the dollar amount I paid an additional $50 for insurance on the parcel to ensure it arrived safely. The machine was fixed and it was sent back with a note from Mr. Griner that said "do not open the machine again or it's gonna cost you". I had previously had my therapist open the machine to see if it needed a new belt since it could be fixed easily this way rather than spend an additional $50 for the shipping and insurance but when it was not a belt issue is when I sent it in.
The machine worked for a few months then broke again and so I was told to send it in again with an additional fee of $50 for shipping and repair so I sent it with a return ship label and an additional $30 because Mr Griner said the repair portion was $30 and I had purchased a return label myself for $10. I own 2 online shops and I use USPS to do all my shipping. I was told that the item was repaired and sent back to me. Well I had the tracking number and the post office has no record of ever receiving it. I never did receive my $600 machine back. I filed an investigation with the USPS and they never had a record of ever receiving this package and the last known whereabouts are when Mr. Griner signed for it when he received it from me. Mr Griner says he sent it from the Los Angeles USPS but cannot provide me any proof or receipt that he in fact did mail this and blames the USPS for losing it. I have mailed out over 400 packages in my online business over the last year and a half as well as used the USPS for the last 25 years for my personal packages and they have never lost a package. There have been delays on occasion but never have they lost one where it was never found.
I tried contacting Mr. Griner and even sent pictures of my near death car accident resulting in chronic pain and a brain injury when my car hit a wall at 95 miles an hour and flipped up and hit a pole and rolled with me in it. I explained that this machine keeps my pain level where I can get out of bed and able to work. I explained that I am a single mom of two small children and need to work to provide for my family and that I am the sole provider for my family. The only thing that happened was he said sorry this happened. Never offered to replace my machine or even offer me one ata discounted rate. I have been unable to perform my job to my fullest as a result of not having this machine that lessens my pain and I have since fallen behind on all my bills and my mortgage payments. I have now lost my 800 fico score and creditors won't stop calling my home. The bank wants to take our home and I am fighting to keep a roof over our head and food on the table because I have fallen behind on everything because my pain levels are so high. I work every day even at the high levels of pain but my work suffers and I am not making the money I used to. All I want is my machine and do not have the desire to sue him in small claims court because I don't have the energy or the money to travel to another state. I believe Mr. Griner kept this machine because he did not like that I opened the machine which is the reason he put the note that it was gonna cost me. I believe he is worried someone will steal his design, I have no desire or knowledge to replicate this machine and just want my machine back or my money so I can buy another one. I spent 11 months saving up money to buy that machine and worked very hard to get it with my own hands as a jewelry designer/artist. This company does not care about their customers.