I had a similar problem with a software company years ago. They only shipped a partial order and then CS tried to deny the remainder of my order.
After weekly calls to CS (I kept notes of names of agents, dates, etc.) and getting no results, I demanded to speak to a supervisor. She rudely informed me there we no error in my order, yada yada yada. I demanded to know who HER supervisor was and wanted to speak to that person. She said she had no supervisor and was the final word and hung up on me.
My next call was to Corporate HQ. I spoke to the VP in charge of the CS Department. [They were located in separate cities.] I politely explained that I had been trying for months to get a resolution to my order problem. I listed dates and CS agents and that some agents said they were shipping the remainder of my order — but I never received anything.
The VP asked me to give him time to invesigate and find out what the problem was. About an hour later, his secretary called me and told me the problem had been resolved and my shorted software was definitely being shipped out that day. [I received it a few days later.]
I did chuckle as the CS Supervisor apparently found out she did have a boss and he was not happy to get a call from a dissatisfied client/customer.
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After reasonable periods of time, move up with chain of authority — even if you end up having to call Corporate. Be nice, write down names and dates and promises, etc.
Back in ‘77, I got back from a two years overseas assignment. My bank (Crocker) has “lost” my account — all $25,000 life savings gone ($100,000 in 2018 dollars). The clerk was useless. The branch manager was useless (”you probably bounced a check”). Went to the library and got the names of the appropriate top execs and the state banking examiner / regulator. Wrote them all polite, detailed letters and named names.
A couple weeks later the branch Manager had changed his tune, was very apologetic and treated me like royalty. I think he was thankful to have been able to keep his job.
I learned that lesson early — don’t my screw around with feeble underlings if you have a serious problem. Go straight to the top.
For this OP’s problem — I don’t think Jeff Bezos is going to step in to solve it.