Lowes Credit Card

I got a Lowe's credit card back in March of 2011 and purchased a washer and dryer. I had been faithfully making payments, plus paying extra to get it paid off before the 12 months/same as cash deal was up. Then, a few months later, I purchased a few other things for 12 months same as cash. Then, a few months ago, I purchased laminate flooring for 18 months same as cash. When I make my payments and EXTRA, this money is being distributed amongst ALL balances, not the one that's due by March 20, 2011!! At this rate, no, the balance due March 20, 2011 will never be paid off. This way they can go back and charge interest from day one, and still get their money. When I make extra payments, I want this put towards the balance coming due FIRST! Otherwise, why am I bothering?? I plan to call them today and go rounds with them. I know they will have some excuse and aren't going to budge. BEWARE!!! Lowe's credit card deals are a scam!!