Bad service

Hi more then a month ago I paid my loan account in full they did a debit order and I paid in cash which resulted in me paying way extra I was informed on 5/12/2017 that I over paid and that it would take 3 days for the refund after visiting the store on numerous occasions,ph calls to both the store,customer care and their complaints office i have not received any communication Its like I'm being blatantly ignored every time I am told that they would call me back and they never do