After multiple calls with the BA India team, I finally reached the Manchester call center and they immediately saw the double charge on my CC with the duplicate new charge when the flight was upgraded with Avios. The refund process has started. (I will post an update if I encounter any additional challenges.)

So I am confused by this process. Are the two computer systems (UK vs India) different or is it a matter of experienced customer service representatives? I am relieved to near the end of this process but still discouraged by the customer service I received, even to the point of being called untrustworthy by the service representative. I was also told it was impossible for the BA ticketing system to charge me during an avois upgrade.

Is there a way to guarantee reaching the Manchester call center?