sleep ease beverly MA Progessive leasing Utah high interest finance, without interest disclosure Beverly Massachusetts

I bought a queen size Mattress in march 2015, 1t price was 2900 i paid 1269.00 downand finance the rest with progressive leasing. The sales man. set it all and only disclosed the interest was high, unfortunately, my high interest thought was 18- 20 percent, not the 60 to 70 percent interest that i am experiencing. I am a Disabled veteran and feel taken advantaged of, I paid 315.00 amonth for 7 months and had been surprized when i saw the 7th payment leave my account. I found a phone number 877-898-1970 and choose to call and inquire about my balance, 10-28-15 and was told 913.51 which I did not have availible and then I called them today 10-29-15 and found I needed 1013.00 to pay it off. Please this is insane and I believe illegal, What should I do, Thank You