I think Tiger Sun has explained it perfectly!
I wanted to talk to someone because we have registered overseas accounts to make transfers to (filled in the forms and everything, got letters confirming they had been registered) but when we do transfers to these accounts using internet banking, they keep bouncing back into our accounts (minus large fees of course) after a couple of days. I have no idea why they are bouncing back and I wanted a quick explanation.
I work from home so don't pass a handy branch every day, and just wanted to quickly ask someone why this was happening and sort out how to fix it. However, apparently that is not what the HSBC hotline exists for, as Tiger Sun pointed out.