kept in the books for a long time and refund never given to me

I would like some advice as to how to proceed. In the tax calculation of 6th of April 2022 to 5th of April 2023, I was working for an employer (a restaurant ) and I paid 685.42 income tax . I left this job and started working on another restaurant but only less than a week, where I left after the week ended. The 685.42 income tax paid in the previous employer was refunded to the place where I only worked a few shifts and left because I realised they were not playing by the book. They kept me in the books for a long time after the end of my employment and told you the wrong end of employment date about a year after I actually finished being employed by them. I never saw that refund that was given to them when in fact I was working with another employer and not with them ( I worked less than a week for them) and it is clear by the dates and the reception of no monies by that employer which my only and main source of income was. Now I have secured myself a permanent job in a reputable company and my wages are going to be arrested, which is given me a lot of anxiety. I never received the aforementioned refund and I can demonstrate that by my statements, so the information that I owe tax to HMRC is a mistake and it is wrong, and if anyone would look the timeline they would realise that I was not working for them and not earning anything with them, so I don't understand why the refund was issued to an employer where I was kept in the books and was earning nothing with them, when it is clear to see that all my income was coming from my only and main employment, however, my only and main employment never saw this refund. I would appreciate any help because this situation is giving me some anxiety as to how to solve this and what is the best course of action I can take. Thank you very very much in advance for your assistance and help. I. do really want to get this situation solved and I would prefer to pay the money upfront to you rather than it being arrested from my wages for 12 months. However, I want to demonstrate that I never received such refund. Yours sincerely, JR

Hi Juan Rodriguez,
To review both your previous overpayment, and the underpayment amount present in your code, we would need to review your tax record.
To allow us to do this, please contact us by webchat or phone here:
Income Tax: general enquiries
Thank you.