Luther Sales I was quoted one price for payoff, now there saying i owe an extra 400.00 new york, New York

I am very dissafied with this company. There customer service is working out o a home. I ordered a computer by payroll, my balance was quoted owing a 100.00 4 weeks again. I called to confirm my balance, they are still taking out alloments. I called to inquire, i got the run around. When i finally talked to someone they inormed me i owe 429.00 dollars. This was a six month agreement. Who can I talk to represent me in why is this company charging triple the amount for there products.