OK, OK. Substitute “one bad experience” with “two bad experiences in a row”.

It is certainly upsetting. I understand the frustration. Mistakes happen. It is not so much a RA issue, as it is an issue with the fulfilling warehouses, whoever those were.
I just went thru two EBay goof-ups in a row on autoparts (and I rarely use EBay for anything). One was the dual mufflers for the ‘08 Volvo XC70 in my sig. The price for low grade stainless steel mufflers and pipes was amazing. The included clamps were a bonus (sleeve clamps), except both clamps were the wrong size. The seller did review the design and sent the correct clamps several days later. The next goof-up was an input pinion shaft seal for the steering rack. Wrong part sent to me by EBay seller. Sent it back. Awaiting refund from EBay. Emailed the seller several times before mailing the part back. Still haven’t received a response. At least with RA, i can play their automated return system game and get some positive response!
Despite the EBay issues, I’ll still buy from EBay.