Refusal to refund over deduction

My long term loan was paid up with mafori finance on the 11 of March, I sent my paid up letters and proof of payments yet the installment went off from my March salary, I enquired with on of their agents and I was told that loan would be paid up upon receiving the payment schedule from my employer, meanwhile I took a new loan with them on 30 March. On the 7th of April i made a follow up with them again and I was told that the refund would be paid in 48 hours, a week went by and i made another follow this is where I was informed that the refund would be used as my first installment. I refuses because that was not the arrangement and I told them this would then mean that they won't deduct for April which they said they will. My problem is that Mafori finance exploits the workers of Mangaung under the pretence of assisting them..