Complaint Review: HSBC Retail Services

I bought furniture from a Levitz store under a promotion scheme which was advertised to give me defered payment for one year. I was told by the Levitz representative to ignore any bills sent by HSBC for the next one year.
About two months later, i received a call from an HSBC collections agent to my surprise he said my minimum payment for $30 was past due and i was being charged a late fee of $10. I explained to him that i bought the furniture under a one year defered promotion plan, however, he said if i did not pay the minimum payment, they would report me to the credit bureau. He also said if i paid $666.51 over the phone, he would waive the late fee and the payment by phone fee and my account would become "regular".

After making the payment of $66.51, I was shocked when i was told by the representative's manager that neither the late fee nor the pay-by phone fee would be waived.
My entire experience with HSBC stinks - wrong billing, fradulent promotion scheme, false promises by representatives of the bank to extract payment by phone and no greviance addressal system.

I am really pissed but do not know what to do to nail their asses. Who can i reprot these guys to ? Any suggestions?
Thanks

Aj
Jersey City, New Jersey
U.S.A.