Ortho Mattress/SNAP Financial Charging me almost 100% interest charge that I never agreed to to finance a mattress

On July 10, 2015, I purhased a mattress from Ortho Mattress located in Cerritos, CA for $817.49.I did not want to use their in-house financing as my credit is recovering and I knew I would not qualify, The saleserson advised me of their 100 Day Same As Cash Promotion, where I could pay for my mattress in 3 payments within of $272.49 100 days with no interest charge, ,erely a $39 provessing fee. I could have paid for the mattress in full. I wish now I had. I  provided my bank routing and account number, as well as my email address and paid the $39 processing fee at the time of purchase. I was told I would hear from SNAP financial to set up the payments. He further explained if I did not respond to them, I would wind up paying 12 months or a total of $1549.72. I laughed when he told me the figure, because there was NO way I would pay $1549.72 for a mattress with a sales price of $817.49...that is insane, I got my mattress in 5 days and never heard from SNAP and of course, I promptly forgot about it. 

I was recently reviewwing my bank statement and discovered that for the past 11 months, SNAP has been deducting a payment of $125.90,for a total of $1384.90...NOT the 3 payments of $272.49 that I agreed to. I contacted both Ortho Mattress and SNAP about what I had discovered and asked how to rectify the error, Ortho has not responded. I did hear back from SNAP who told me that they emailed me when muy account was openede on 7/16/2015. I never hvwe heward from them before I contacted them today, They said my account was set up for 12 payments of $125.90 or a totalk of $1549.72. SNAP further told me the good news was that I only had one more payment before my account was paid in full, lol. They sent me a contract that I supposedly signed that was set up from the get go for 12 payments. This is why I never heard from them. I think that the salesperson who sold me the mattress at Ortho filled out the paperwork incorrectly and set my account up for the 12 months at almost 100% interest. I checked the contract they sent me, There is a place for a signature, but that appears to have been done electronically as what is on the form is NOT my handwriting. Rather, it appears to be a computer generated font. 

I replied to SNAP with a cease and desist statement informing them I was revoking any access to my bank account. I have hot heard back from them yet, I have also notified Orrtho via email, to which I have had no response. I intend to notify my bank of the fraudulent charges I never athorized.