Refund received after my contract is finished

Dear Sir / Madam I resigned from the company in mid-January as my one-year part-time contract with the company concluded. In early February, I unexpectedly received a payment from HMRC. However, I have not received any notification (e.g. P800 notice) from HMRC. Where can I find details about the refund? Thanks a lot.

Hi,
If you have an online account:
Personal tax account: sign in or set up you should be able to view the details of the repayment.
Alternatively if you contact HMRC we can check this for you:
Income Tax: general enquiries
Thankyou