If you have e-filed your return and do not receive tax refund within a reasonable period, you should check if ITR-V of return was verified or not (you may check it on our mobile app for free). Return will not be processed till the ITR-V has been verified.
In case ITR-V is already verified and still there is some delay, you can follow up with the Centralized Processing Centre (CPC) of the Income-tax Department on 1800 4250 0025 or 080-2650 0025.
If you filed return for previous years, then you can write a letter to the Jurisdictional Assessing Officer. Also, don’t forget to attach your Income tax return copies with this letter.