HSBC Retail / Best Buy 6 Months Same as Cash Scam - Watch those deferred interest charges. Internet

My 6 month same as cash promotional loan balance was due on 12/22/11.
I called and paid the balance over the phone with a representative in India, who took care of me.
When I received my next statement from Best Buy (based on their online statements that are never updated properly, I will never  go paperless), the promotional balance showed as a previous balance and my new balance was the deferred interest charges.
I immediately called HSBC and spoke to a floor supervisor.  He proceeded to tell me that because I paid this outside of my billing cycle, the charges were applied.   I argued with him for a while and he
finally said the charges would be reversed and reflected in my next statement.   I will wait and see
what that statement will show.  I have another promotional coming due in March, so I cannot wait for that one.
I will be closing this account down after March.   HSBC Retail, I believe, is Household Finanace.  I wonder how many other people this has happened to that may not be aware of it.   Read your statements !