I hate to inform you, but this is not a a scam. This is something that is clearly disclosed in the documentation you signed or otherwise agreed to.
Yes, The salesman who's paid only comission for every sale didn't say, Oh and BTW, while I have you interested and ready to pay for this right out let me warn you that after 12 months, you will have to pay the entire loans' balance of interest if it's not paid in 12 months". That's not something he's paid to do, he's there to sell you a rug and get the hell out of there. Its your job as the consumer to make sure you read everything BEFORE you sign. Only if something is not disclosed on paper, you are not liable for such charges. If you didn't read the fine print, well sucks to be you buddy. Be happy you only got charged 30% interest, I've seen them as high as 50% or more.
I've worked for a bank for years, and this type of business has been out there for quite some time. "No Payments, No Interest for 12 Months" always means, 12 months, No interest ONLY IF YOU PAY IT OFF". Yes, it's not clearly disclosed in the title of the loan application, but with anything dealing with YOUR money, you MUST read every bit of fine print before you sign.
Mind you, I fuggin hate empire carpets, their salemen are complete tards, but this is not their fault. This is your negligence.