Mobicred refusing to refund my money

I bought a few items using Mobicred. Then requested a settlement amount. They ignored my mail for more than a week. Then decided to pay the whole balance. Only after I have paid the balance in full they send the settlement amount. Subsequent to that one of the retail shops refunded the money in error to this account. I wrote a letter to them requesting them to refund this money directly to my bank account so that I can pay retail shop directly. They haven't responded and it's almost a week now. They are so quick to debit our bank accounts but they don't want to refund.