You have not mentioned the date on which you have file your ITR and date on which you received the email that “your ITR has been processed with a refund. ” 
Still
Please note that after completion of processing of income tax return, It may take upto 30-40 days to get the refund credited in your account. In some cases refund is credited in just one day but in some cases, it may take upto 30-40 days. 
If your ITR was processed about a month before but still the refund is not getting credited, you can initiate a refund reissue request through the website of the income tax department (www.incometax.gov.in)
step to initiating refund reissue request are given below:-

1. Login to income tax portal.
2. Go to Homepage.
3. Go to Services Menu.
4. Select Select Refund Re-issue. 
5. Then CLick “Create Refund Reissue Request” and submit your request. 

If there was a failure in an earlier refund issue transaction then you will get your refund after this request.