Product: Debt collection

i have had this account with this furniture store since XX/XX/XXXX. this is my 3rd account with them, the other 2 have already been paid off. I have been on a auto-pay direct monthly payments coming directly out of my checking account. Scheduled payments coming out the last day of each month. I called the company in XX/XX/2017 and requested to postpone the last and final payment scheduledXX/XX/XXXX, until the last day ofXX/XX/2018, of which they verbally agreed to do so over the phone. on XX/XX/XXXX, i start getting phone calls from them saying they have not received final payment, that my debit card was not working. I told the girl that whatever debit card they have on file for me was no longer valid, and asked her if they didn't have my direct checking acct info on file, since they were taking monthly payments out all this time? she responded, " yes, they did '', and i asked her to repeat my checking account info back to me ( to  make sure she had the correct info ), of which she did. at that time, i gave her my permission to process and post the final payment for {$170.00}. That was the end of that ( so i thought! ), until i  started getting calls the next day, friday, XX/XX/XXXX, from them stating that i owe them a payment of {$400.00} plus, I told them I did not owe that much, then they said I owed {$300.00} plus, I told them " no '', then they said I owed {$200.00} plus, again I said, " no I don't! This i did not understand, they totally sound like crooks! I called my bank, to see if there was a payment in the amt of {$170.00} taken from my checking acct ( of which there wasn't )! I called them back & tried to explain to them what transpired the day before, and that i didn't understand what went wrong?! they kept insisting that i owe more money. i told them i didn't. all throughout the day, they kept calling, at least 10 times, harassing me about the payment. I told them to stop calling and harassing me and that I was going to call my attorney and report them. Finally, i told a young man named XXXX on friday evening ( XX/XX/XXXX ) on the phone that I only owed {$170.00}, but he insisted that i owed more, in the amount of over {$200.00}.! each person that called me throughout the day on XX/XX/XXXX, to harass me, gave me different amounts that they said I owed, so ridiculous! The harassing phone calls kept persisting, calling me continuously! on monday, XX/XX/XXXX, i spoke to a supervisor who threatened me that he was going to report me as 67 days delinquent on my account and that i owed in the amount of over {$200.00}! At that i told him that I was going to call my attorney and to stop calling me! As i look at my contract, i see that my last and final payment was only to be {$170.00}, not {$170.00}. They have all this information of the conversation that transpired between myself and a customer rep back in XXXX and the verbal agreement that was made. I have no idea why they did not try to take the payment out of my checking account, like they had done since the beginning of the contract. Now they are trying to extort more money from me than I owe and have threatened to report me as " delinquent '' to the credit bureau. This is All their fault in the first place! I have nothing to do with their " mistakes ''. By the way ... they have tried in the past, with my last 2 accounts with them, to extort more money out of me than was actually owed, for the last payment, saying I owed more than I really did, but i refused to allow this nonsense and they stopped when they saw, I would not go along with it! They are crooks!