Rebate for one tax year now same amount requested back from previous

Hi got a taxi rebate for last tax year of nearly £400 at the start of October. Today I got an email saying I owe basically the same amount for the tax year previous to that one. This seems really unfair. I tried to call but my call was terminated due to the long queues. What can I do about this? Thanks

Hi,
This forum is for general queries only and is intended to help you self-serve. We are unable to provide specific advice tailored to individual circumstances.
You may wish to contact our team for advice:
Income Tax: general enquiries
Thank you