Minimum Payment/12 months deferred interest acct

I purchased furniture from Value City furniture. I received a copy of their credit card agreement which is through WFNNB. The agreement says clearly that the minimum payment on deferred interest acct's will be 1% of the balance. They are billing me at 3.5% and when I called I was treated very rudely and was told they will put my acct in dispute and hung up on. Without a doubt, the worst customer service in the world. The rep didn't even know their own credit card agreement rules and denied that it said it. I read it to her twice and she still denied that it stated what I read her.