Newell Rubbermaid Inc. Customer Service Issues

I am extremely dissatisfied with the customer service I have received. My husband and I bought a shed from Home Depot. When my husband tried to build it, we discovered that we were missing part C from model # [redacted]. I contacted Rubbermaid online, and after numerous attempts, I finally reached someone who assured me that we would receive the missing part in 7-10 days. However, it never arrived. I then tried calling the customer service number I found online and was on hold for almost an hour without speaking to a representative. I also contacted them online again but received no response. We purchased the shed in April and have not received any updates regarding the missing piece. We are frustrated as the shed should have been assembled by now. We invested a substantial amount of money in this product, and it has been exposed to the elements due to the missing piece. I am now requesting a refund, and I hope to hear back promptly.