unpaid refund

i purchased an item on takealot app 18.1.23 it was collected at pickup point on19.1.23..after i checked item when i received it,it didnt have batteries like advertised so i logged return immediately for refund and it was collected 20.1.23 and i received email that return refunded but until today it was not refunded i checked on account it has not been refunded instead interest has already been added for a item that i returned and was supposed to be refunded and now mobicred is telling me im liable for interest because takealot did not refund before there payment date.im very dissappointed in this service as i regularly purchase from takealot.i have emailed takealot and tried calling no response.