Meubon Oxygen Store review: Warning about Meubon (meubon.com / Mayerwood Retail LLC) — documented return-label and post-refund charge issues

Posting this as a factual account in case anyone is researching this company before buying, especially since they sell oxygen concentrators and similar medical equipment that often gets bought for elderly or chronically ill family members.
I bought a portable oxygen concentrator (~$970) from Meubon in May 2025 for my father. We ended up not needing it, so I requested a return while it was still sealed and unused.
Here's what happened, with the parts I found concerning.
The return label didn't go to the company.
The "return label" they sent listed me as the sender and an unrelated private individual at a residential address in another state as the recipient — not Meubon, not a warehouse, not any business address.
That's not a return; functionally it's asking a customer to forward merchandise to a stranger's house. I declined and asked why I wasn't shipping to their Texas warehouse. They told me customers "cannot dictate the return procedure."
I filed complaints and disputed the charge.
I filed with the BBB, the FTC, and my state Attorney General's consumer protection division (which opened a case), and disputed the charge with my credit card company. The chargeback was resolved in my favor.
Almost a year later, they resumed contact and escalated.
They sent a "final demand," a "litigation hold" notice, and then provided a new return address — which I verified is a unit in a 288-unit residential apartment complex, listed as their "Authorized Return Receiving Location." Same pattern as before: a residential address, not a business facility.
They invented a new charge under pressure.
About ten minutes after they cc'd a state AG investigator on their correspondence, they emailed a brand-new $540 "battery replacement" charge, claiming the batteries degraded from sitting unused — with no inspection (the box is still sealed), no invoice, and no part number, demanding payment before I'd even shipped anything back.
I've since returned the device via UPS at my own expense with signature confirmation and full documentation, and rejected the $540 charge in writing. All my complaints remain on record.
Why I'm posting
Not to relitigate my own situation, which is essentially resolved. It's so the next person searching this company name finds something.
A few separate things to be aware of if you're considering them:
Their published return address (on meubon.com/pages/refunds-returns) is a residential apartment unit.
There are existing 1-star reviews and complaints on Trustpilot, BBB (Houston), and ComplaintsBoard, several describing batteries that stopped charging and unanswered support requests.
A patient on a pulmonary forum reportedly noted the device's own spec sheet shows very low oxygen output at higher flow settings — worth verifying independently before relying on one of these for medical oxygen.
Document everything in writing, pay by credit card (not debit or bank transfer) so you have chargeback protection, and think carefully before buying medical-grade oxygen equipment from a seller you can't verify.