Disreputable Company Practices

Why would a company who advertises hassle free 90 day returns refuse to give me a return authorization for perfectly good merchandise? Why would a company not want their merchandise back to sell to someone else? Why would a “reputable” company not have /supply customer service phone numbers for those who want to talk to a human?
Do the words “shady” or “questionable” mean anything to Cellular Outfitter? I have been exchanging email with this company for two weeks trying to return merchandise that was shipped to me in error. It was not what I ordered. Meanwhile they keep my money and I do not have the merchandise that I wanted. It feels like this company is trying to stall me until my 90 days runs out.