Tax on bank interest

Hi please can you tell me an address to contact about finding out about sources of untaxed interest that have gone into my tax code calculation. I have significantly less than the thousand pound threshold but my tax code calculation is reducing my personal allowance as if HMRC have been told incorrectly. Thank you

Hi cheryl,
You can contact us either by letter or phone to obtain the information.
Please see here:
Income Tax: general enquiries
Thank you.