Capfin *****s

I had a loan with Capfin of which I wanted to settle, I called the call center they gave me an amount, after waiting for a while decided to do the self service settlement by using the ussd string, the sms came through with an amount and a link that goes to my banking app approving the payment, the full amount as per the sms and link went through, today I'm still getting calls about me owing them R300 and some change, I get a debit order sms reminding me of my payment that should go off but I finalized payment, please check ur system and clear my name and as for agents calling me about R300 I'm not paying for that why don't ur settlement amounts agree if it's the same company