Mortgage Relief - How long to come through?

Hi
We closed the sale of our house on the 20th March and on that date i sent in the relevant form to the Revenue for mortgage relief. My first mortgage payment is due out on the 21st of April and I am just wondering would mortgage relief take effect by the time by first repayment is due or does it take longer to come through?

It took 3 months to come through for me but you can email revenue and ask them and they are usually good at responding.