angry customer

Im very frustrated wih this company i too a contract out with them for 398 a month. i have never ever skipped a payment since being with them now they want too send me statements that i owe them 1586.99 what day light ******* are they try too do here iv'e been sending mail they can not answer how they got too that amount or proof that i skipped a month .i requested a password reset they refuse telling me my bill is otstanding an they will collect they are the worst people make sure you dont get ****** by these people im actually disgusted in how they even just out of the blue let the customer kow u owe this whith no explaination when u signed a contract on 398 and never skipped