Bad service/Being charged while I settled the account

I purchased 3 deal blankets December 2018 ive never missed any payment instead I paid upfront i paid R1620 end may Homechoice sent me an sms saying that i still owe R35.52 I paid it the following day again they sent me another sms saying that i owe R6.92 I called I requested a full and final settlement offer letter which sent to immediately,I paid it the following day on the 31st may it says it’s valid till 07 june. I demand this ****en company to close the account the account and update my ITC as I don’t owe them anything,I want them to remove my number in their database I cannot deal with people who are ripping people off and I need my paid up letter OTHERWISE I WILL TAKE THE MATTER TO OMBUDSMAN I fail to understand why this company still exists,I feel like im not being treated fairly and with respect,im a customer ..