HSBC blacklisting expats in Africa?

HSBC has taken the decision to close my accounts without explanation. Could it be because I live and work in Africa? A friend writes: 

"I too, have had an HSBC account for 30+ years. Recently, they had me fill in a customer account review. A couple of weeks later, the bank asked me to come in. They weren’t happy with the fact that one of my addresses was in Africa. But although the staff were as confused as I was that there was a query on my account, they were also a bit politely suspicious of me."