Need an advice on Harassment

Sir 2018 I have purchased an Air condition in store on HDB financial services, I paid some down payment and they forced me to take extra warranty for the replacement of parts in case of any repairs, unwillingly I took it. For few months Almost for 6 months I paid with out any interruption. But due to my financial I couldn't able to pay loan on exact dates for those cheque bounces I paid on the same month with fine. During pandemic I asked them for moratorium, They said ok, Mean while My purchased product got repaired, for that I looked up for extra warranty ,approached HDB financial services, They have sent an technician ,he looked at said that part has to replaced for that it costs 6500/-, again I have approached the HDB services for warranty, they rejected saying that you have one cheque bounce , so you couldn't avail it, they didn't explained about this terms and condition before taking. one side fighting with them, I have cleared all the amount. last one year onwards they are harrasing me though I cleared the amount,Instead of giving my Insurance amount I have to pay 6500. Now they called my friend and threatnd him that they will file a case in police station,we will drag you to court, we will send court notice to you. But I have paid all the amount .Now please give your solution.