Did you query ATC on the initial altitude? What did they say? FAA JO 7110.65 contains the ATC clearance contents (policy, content and phraseology) for ATC personnel.
Each company (and/or union) normally has an ATC Rep. Have you contacted anyone? I would recommend filing an internal company safety report, ASAP if needed, and work it through the union. Also, your company could reach out to the POI, who would then coordinate with the Regional All Weather Ops/NextGen Branch Office (XXX-220) . The -220 folks have direct communication with ATC facilities within their Region of Responsibility. Hope this helps!