Once the refund has been approved by Apple, it will be credited back into the user’s eWallet within 30 days.
Below are the articles that may be useful for you :
How do I request a refund for App Store and iTunes Store purchases?
What should I do if my money is being deducted from the Touch ‘n Go eWallet but not reflected on App store?
What should I do if my funds were wrongly deducted?