7-10 Working days for a simple refund

Good morning

Im writing this with frustration and anger as im trying to grasp on the concept that when i make a card payment to one of your merchants funds leave my account immediately but when its time to receive my refund it takes 7-10 working days while the merchant has settled their POS and have stated that the funds have left their account. Where is my money and who's gaining interest from it during those 7-10 working days... I gave back the goods i bought so i need my money.

Regards

Muntu Ledwaba