I'm appalled by this RCS company and their service

I have never felt so harrassed by a company such as RCS I had a loan account that I called through to settle last year 21 Nov 2017.I called in for a settlement loan amount which I paid the very same day.I kept on calling them to confirm if they have received my proof of payment in which I was asked repeatedly to resend.i then called them again and the one team leader advised me that he can see on their system that the payment was received but I wasn't removed on the system however my debit order will go off.In which he requested I visit my bank to have it reversed.To my suprise I have been receiving SMSes that I am still owing.I called again demanded to speak to higher management to request that why am I still owing when the settlement was given by their consultant and they can listen to the recording if they want to.I demanded to have someone call me back to settle this.till this date no one has called me instead I received an SMS today to be told I am handed over