Unfairly billed

Hi.My wife went to Southgate Dis-Chem to get a quote for appliances that was to be paid through the medical aid. It was stated that we need the nappi codes and figures on the quote so that the medical aid can process the quote and give the approval. This was. Little lengthy due to the process and all went well till day of delivering. We were called to be notified that there is a shortfall on the one product. I requested more information as to why there is a shortfall as the medical aid approved the claim. I was now notified that the quote was given for a cash transaction and not a medical aid claim. This is so frustrating .Is there error now our problem?This is really very unfair. There mistake is costing us funds that we really did not budget on.How many others suffer the same unfairness.