Week 2 and still waiting for a refund

My loan was fully settled on the 19th September and and a debit order went off on the 23rd for R2985,32 , I have been for a refund for the amount that went off on the 23rd as the loan is fully paid off. I provide them with proof of payments and to date there has been no refund, not even a call to acknowledge my request???? Its week 2 and the payments should have reflected last week already!!!!